Tag Archives: rainforest

Australia returns control of the world’s oldest tropical forest to indigenous First Nations

The Daintree Rainforest is part of the oldest continuous-growth rainforests in the world and is recognized as such, being part of a UNESCO World Heritage site. Now, Australia’s government has returned control over this ancient forest to the First Nations peoples as the first step towards reconciliation.

The Daintree National Park, part of the Wet Tropics of Queensland World Heritage Site, protects a 135-million-year-old tropical rainforest. Before European settlers ever set foot on Australian soil, the indigenous First Nations peoples lived in this area, as they did in others across the continent.

As a first step towards addressing an “uncomfortable and ugly” past, the Australian government will be returning this land to its original owners.

Returning the heritage

“The Eastern Kuku Yalanji people’s culture is one of the world’s oldest living cultures and this agreement recognises their right to own and manage their country, to protect their culture and to share it with visitors as they become leaders in the tourism industry,” said Queensland state environment minister Meaghan Scanlon.

The Daintree jungle is a rich ecosystem, harboring ancient and rare species. Some of the plants and animals here have remained relatively unchanged for millions of years. Some of the fern species here have been around since dinosaurs still roamed the Earth.

Its wealth of biodiversity and sheer age have won Daintree and the wider Queensland Wet Tropics a World Heritage status. Much like the rest of the continent, this land is under the administration and care of the Australian government. The Ngalba-bulal, Kalkajaka, and the Hope Islands National Parks will also be returned alongside Daintree. In total, this amounts to 160,000 hectares (around 395,000 acres) of land on the Cape York peninsula.

Initially, this land will be jointly managed by the First Nations and the Queensland state government, to ensure a smooth transition. In the end, however, First Nation peoples will retain sole administrative power over the area.

To date, the Australian government has returned roughly 3.8 million hectares on Cape York to Indigenous traditional owners.

“Our goal is to establish a Foundation to provide confident and competent people with pathways and opportunities for mentoring, training, apprenticeships, work experience and employment for our Eastern Kuku Yalanji Bama to fill positions from a wide range of skilled trades, land and sea management, hospitality, tourism, and research so that we are in control of our own destinies,” said Chrissy Grant, Eastern Kuku Yalanji Traditional Owners Negotiating Committee Member, in an official statement.

“On 29 September 2021, this significant historic event becomes legal and a reality for the Eastern Kuku Yalanji Bama to realise our vision for a more promising future for all our people.”

This handback will create the first place in Australia where Traditional Owners will both receive ownership of and have an important part in jointly managing an UNESCO World Heritage Area, according to the same statement. Officials are confident that giving administrative power over this unique ecosystem to those whose cultures and customs were shaped in their midst is the best way to ensure that they remain protected and preserved for future generations.

Life in the tropics could become impossible if we don’t reduce our emissions

If we don’t limit global warming to less than 1.5ºC the tropics could become uninhabitable within a few decades. Life in the equatorial region, home to about 43% of the world’s population, could also become intolerable.

Image credit: Flickr / Hanming

Countries vowed to limit temperature increase to 2ºC, ideally aiming at 1.5ºC, in what is called the Paris Agreement. Half a degree may not seem relevant but it actually is for many regions of the planet. The global average temperature has already risen over 1ºC compared to pre-industrial times, and if we want to limit further increase, we need to take drastic action — fast.

In a new study, Princeton University researchers wanted to see how a warming climate would affect our ability to inhabit the world’s hottest places. They focused on a measure known as the wet-bulb temperature, which accounts for heat and humidity. The body cools itself through sweating and the evaporation of sweat from the skin. But this has a limit. Scientists argue that humans can tolerate a wet-bulb temperature of up to 35ºC (95 ºF). Beyond that, we are in trouble. 

The human body normally has a stable internal temperature of around 37ºC (98.6 ºF). Skin temperature has to be a bit lower so to allow core heat to flow to the skin. If it’s not, a person’s internal temperature could rise quickly. “If it is too humid our bodies can’t cool off by evaporating sweat,” Yi Zhang, study-lead, told The Guardian. “High body core temperatures are dangerous or even lethal.”

The researchers focused on how global warming could affect wet-bulb temperatures in tropical areas such as the Amazon rainforest, the Indian peninsula, parts of Southeast Asia, and a large part of Africa. They found that even before the 1.5ºC threshold, there could be adverse health effects. But after the threshold, things can get very bad very fast. Mojtaba Sadegh, an expert in climate risks at Boise State University that wasn’t involved in the study, told The Guardian that if this limit is breached, “infrastructure like cool-air shelters are absolutely necessary for human survival.” Given that much of this effect would happen in developing countries, that seems very unlikely to develop.

Climate urgency

The new research is just the latest scientific warning over the severe dangers posed by extreme weather events. A study last year found the impact of high temperatures on hospitalizations due to cardiovascular diseases has increased in Australia over the past two decades. Cardiovascular diseases are the main cause of mortality and morbidity worldwide.

This highlights the need for further climate action to tackle the growing greenhouse gas emissions. New climate pledges are expected this year by the United States, China and the European Union, the world’s largest emitters. With the world’s current efforts, climate experts estimate the global average temperature could reach 3ºC by the end of the century. 

The study was published in the journal Nature GeoScience. 

In 10 to 20 years, it will be so hot that tropical trees live shorter lives

It’s not the best time to be a tropical tree, as rising average temperatures risk impacting their lifespan.

Image credits Roel Brienen.

A new study explains that the longevity of trees at the tropics is shortened by higher temperatures. The findings help further our understanding of how climate change will impact ecosystems in the area and its effects on the rest of the planet. The team argues this is the first direct evidence that tropical trees experience shorter lives in hotter environments, and that forests all around the world will be affected.


“Many regions in the tropics are heating up particularly rapidly and substantial areas will become warmer, on average, than approximately 25 °C,” says Professor Manuel Gloor at the University of Leeds, a co-author of the paper.

“Our findings – which are the first to demonstrate that there is a temperature threshold – suggests that for trees in these regions, their longevity is likely to be negatively affected.”

The temperature above which trees become affected is 25 °C, the paper explains. This result is based on four years’ worth of tree ring data recovered worldwide. Roughly 100,000 trees from 400 species in 3,000 sites across the planet formed the dataset. All in all, the team reports that although tropical trees grow twice as fast as those in cold areas, they also live shorter lives (186 years vs 322 years on average).

Average temperatures in tropical forests today sit between 21 °C and 30 °C depending on location. These averages will rise alongside the rest of the world to around 2.5 °C above pre-industrial levels over the next 10 to 20 years. The effect this will have on trees varies depending on exactly how much hotter it gets. Changes in precipitation patterns (another effect of climate change) are going to exacerbate this ever further.

Substantial areas of today’s rainforests will see significantly lower tree longevity. They only cover 7% of the Earth’s surface, but harbor around 50% of its species of plants and animals, and a corresponding 50% of the planet’s carbon stocks. Any change here will have strong, global echoes for habitats, air quality, and carbon scrubbing ability.

“These results are a warning sign that, along with deforestation, global warming adds extra stress on the Earth’s tropical forests,” says Dr Roel Brienen from Leeds, paper co-author.

“If tropical trees die earlier, this will affect how much carbon these forests can hold, raising concerns about the future potential of forests to offset CO2 emissions from fossil fuel burning. It could also cause changes in biodiversity and a decrease in the number of species on the planet.”

Tropical forests in South America are closest to this threshold, but they’re not the only ones at risk. Even the Congo Forest in west Africa, the world’s second largest but with lower average temperatures, will be affected.

The saddest finding here, in the words of co-author Marcos Buckeridge, Director of the Biosciences Institute of the University of São Paulo, is that it’s “unavoidable”. It’s too late to stop average temperatures from passing this threshold “even if we were to take drastic emissions reductions measures”.

The paper “Global tree-ring analysis reveals rapid decrease in tropical tree longevity with temperature” has been published in the journal Proceedings of the National Academy of Sciences.

Scientists find evidence of ancient tropical rainforest in Antarctica

Illustration of the Antarctic rainforest. Credit: Alfred-Wegener-Institut/James McKay.

The icy continent of Antarctica wasn’t always the barren landscape that we all know today. As early as 90 million years ago, the continent may have been covered in a temperate rainforest, similar to what you’d find in today’s New Zealand, instead of an ice cap.

The study was carried out by an international team of experts who analyzed preserved roots, pollen, and spores found in cores of sediment drilled within 900 kilometers of the South Pole.

Map of the drill site and how continents were arranged 90 million years ago. Credit: Alfred-Wegener-Institut.

The fossilized soil is estimated to be 90 million years old, placing it in the mid-Cretaceous, a geological period during which the dinosaurs were at their heyday.

This was also the warmest period in the past 140 million years, with temperatures easily reaching 35 degrees Celsius in the tropics. Sea levels were also a staggering 170 meters (560 feet) higher than today.

However, not much is known about what the environment looked like in the South Pole during that period.

Researchers knew they were on to something when they noticed a strange color in a section of a sediment core drilled into the seabed near the Pine Island and Thwaites glaciers in West Antarctica.

“During the initial shipboard assessments, the unusual colouration of the sediment layer quickly caught our attention; it clearly differed from the layers above it,” said first author Dr Johann Klages, a geologist at the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research in Germany.

Germany’s icebreaking research vessel POLARSTERN, operated by the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI). Credit: Alfred-Wegener-Institut/Johann Klages.

Upon analyzing this section with computer tomography techniques, the scientists came across a dense network of fossil roots. The samples were pristinely preserved, allowing the researchers to make out individual cell structures. There were even remnants of flowering plants — the earliest ever found at such high Antarctic latitudes.

In order to establish the climatic conditions of the time, the team compared the environments in which the fossilized plants’ modern descendants live. They also took into account temperature and precipitation indicators within the sample.

“It was particular fascinating to see the well-preserved diverse fossil pollen and other plant remains in a sediment deposited some 90 million years ago, near the South Pole,” said Professor Ulrich Salzmann, a palaeoecologist at Northumbria University and co-author of the new study.

“The numerous plant remains indicate that the coast of West Antarctica was, back then, a dense temperate, swampy forest, similar to the forests found in New Zealand today,” he added.

The analysis suggests that the annual mean air temperature in the South Pole at the time was around 12 degrees Celsius. For comparison, that’s two degrees warmer than the mean temperature in Germany today.

Summer was much warmer, with temperatures hovering at around 19 degrees Celsius, while rivers and swamps were likely around 20 degrees in temperature. Regarding precipitation, Antarctica was probably as rainy as today’s Wales.

Considering these climatic conditions, Antarctica was completely ice-free. This was despite a four-month polar night, meaning for a third of every year there was no life-giving sunlight at all.

“The preservation of this 90-million-year-old forest is exceptional, but even more surprising is the world it reveals. Even during months of darkness, swampy temperate rainforests were able to grow close to the South Pole, revealing an even warmer climate than we expected,” said Professor Tina van de Flierdt, from the Department of Earth Science & Engineering at Imperial College London.

Antarctica’s surprisingly warm and tropical past suggests that carbon dioxide levels in the atmosphere were much higher than expected during the mid-Cretaceous period, which lasted from 115 to 80 million years ago. According to the researchers, CO2 levels may have been as high as 1680 parts per million (ppm), roughly four times higher than they are today.

“Before our study, the general assumption was that the global carbon dioxide concentration in the Cretaceous was roughly 1000 ppm. But in our model-based experiments, it took concentration levels of 1120 to 1680 ppm to reach the average temperatures back then in the Antarctic.”

The findings were published in the journal Nature.

Shifting away from monocultures would benefit both wildlife and people

Agriculture can help insulate wildlife from the worst effects of climate change, but only if it ditches the current focus on monocultures.

Hill slopes in the Nilgiris Mountains, India, being prepared for planting mixed vegetables.
Image credits Rafeek Manchayil / Flickr.

Farmlands can act as havens for wildlife species in a world where climate change is eroding their habitats, a new study explains. However, for that to happen, a shift needs to be made towards mixed cultures. Such a change would also make the farms themselves more resilient against climate changes, which would also benefit us and help solidify the global food supply against environmental shocks.

Although the study focused on bird species in Costa Rica, the team explains that birds can serve as a “natural guideline” for the health of other animal families throughout the world, as well.

Strength in diversity

“Farms that are good for birds are also good for other species,” said Jeffrey Smith, a graduate student in the department of biology and a co-author on the paper. “We can use birds as natural guides to help us design better agricultural systems.”

The team looked at long-term farming practices in Costa Rica and how these impact local bird biodiversity levels. Overall, farms that plant diverse crops can provide habitat for a larger number of bird species than monoculture farms, they found, and are also more stable as habitats over time. Diverse farmlands were also more effective at insulating the species they housed against the ecological damage caused by climate change.

Tropical areas and the rainforests that thrive there are “expected to suffer even more intensely” due to climate change than other areas, explains Gretchen Daily, director of the Stanford Natural Capital Project and the Center for Conservation Biology, and a senior author on the paper. Climate change will lead to longer dry seasons along with more and longer intervals of extreme heat, which will lead to more forest dieback — the process in which woody plants start dying from the leaves (and other peripheral parts) down due to harsh environmental conditions, pathogens, or parasites.

Climate change is already having an impact on wildlife, and, given the tectonically-slow rate of international action on the issue, there’s little reason to believe this effect will end soon. The paper explains that farming practices “really matter” when trying to boost climate resilience and protect biodiversity. Given the speed with which ecosystems can completely break down, and considering the importance of ones such as the Amazon Rainforest in the global carbon cycle, that’s definitely something we should be working towards.

As tropical areas are one of the most biodiverse in the world, the team focused their study on Costa Rica, using birds as a proxy for biodiversity at large.

Tropical Troubles

The Great Green Macaw is an endangered bird species that benefits from diverse farmlands.
Image credits Susanne Nilsson / Flickr.

As rainforests are cut down to make room for plantations of bananas or sugarcane, the amount of habitat available for wildlife shrinks — we’ve been clearing a lot of forest in the last few years, so that available habitat has shrunk quite dramatically, the team explains. At the same time, climate change is making dry seasons longer and hotter, placing even more strain on the animals living here and the plants which support them.

“It’s the one-two punch of land-use intensification and climate change,” said Nick Hendershot, a graduate student in the department of biology and lead author on the study.

“Wildlife populations are already severely stressed, with overall decreased health and population sizes in some farming landscapes. Then, these further extreme conditions like prolonged drought can come along and really just decimate a species.”

The study drew on 20 years’ worth of field data to map which species of birds live in natural tropical forests and in different types of farmland. Costa Rica has various agricultural systems in place throughout the country, which gave the team a chance to compare and contrast monoculture systems, diversified multi-crop farms, and natural forests. Monoculture farms analyzed in the study included pineapple, rice, or sugar cane, while ‘diversified’ farms either mixed several types of crops or were bordered by ribbons of natural forest.

All in all, diversified farms harbored more species of common birds, but also provided shelter for some of the most threatened ones — species such as the Great Green Macaw and the Yellow-naped Parrot, listed as Endangered and Vulnerable, respectively, on the IUCN Red List.

In farms that practiced intensive monocropping, however, the team found that biodiversity levels declined over time.

“Which species are in a given place makes a huge difference — it’s not just about numbers alone, we care about who’s there,” said Daily.

“Each bird serves a unique role as part of the machinery of nature. And the habitats they live in support us all.”

There is a lot of room to expand on diversified farming, both in Costa Rica and around the world, the team reports. It wouldn’t benefit just wildlife — mixed farming practices have been shown to boost crop yields, and they increase food security by making the crops more resilient against environmental shocks.

“There are so many cash crops that thrive in diversified farms. Bananas and coffee are two great examples from Costa Rica — they’re planted together, and the taller banana plant shades the temperature-sensitive coffee bean,” Daily added. “The two crops together provide more habitat opportunity than just one alone, and they also provide a diversified income stream for the farmer.”

I’d call that a win-win!

The paper “Intensive farming drives long-term shifts in avian community composition” has been published in the journal Nature.

Tropical forests and coral reefs are buckling under interacting threats

Climate change, extreme weather, and human pressure are causing ecosystems across the tropics to collapse, a new study reports.

Image via Stokpic

The authors analyzed over 100 locations where tropical forests and coral reefs have been affected by hurricanes, floods, heatwaves, droughts, fires, and other types of extreme climate. The findings expand our understanding of the health of these ecosystems, especially in the wider context of climate change and damage caused by human activity.

The findings weren’t encouraging. The team echoes previous research and warns that only decreasing CO2 emissions can help reverse the damaging trend of climate change on ecosystems.

Compounding issues

“Tropical forests and coral reefs are very important for global biodiversity, so it is extremely worrying that they are increasingly affected by both climate disturbances and human activities,” says lead researcher Dr. Filipe França from the Embrapa Amazônia Oriental in Brazil and Lancaster University. “Many local threats to tropical forests and coral reefs, such as deforestation, overfishing, and pollution, reduce the diversity and functioning of these ecosystems. This in turn can make them less able to withstand or recover from extreme weather.”

“Our research highlights the extent of the damage which is being done to ecosystems and wildlife in the tropics by these interacting threats.”

Climate change is causing an increase in the frequency and strength of storms and marine heatwaves, which are very damaging to coral reefs; they both reduce the cover of live coral (i.e. they shrink reefs) and cause long-lasting changes in coral and fish communities, which reduce their ability to reduce further impacts.

On land, tropical forests are also threatened by more frequent and extreme hurricanes, the team explains. Such storms cause the destruction of plants which in turn affects the whole of the ecosystem, as animals, birds, and insects directly rely on the plants for food and shelter. The team explains that in some regions, such as the Caribbean, extreme weather events have decimated wildlife by more than half.

Finally, the interplay between higher average temperatures and shifting precipitation patterns has led to a rise in large-scale wildfires in the tropics, the team explains.

“We are starting to see another wave of global extinctions of tropical birds as forest fragmentation reduces populations to critical levels,” explained Dr Alexander Lees, from Manchester Metropolitan University, co-author of the paper.

The team took the 2015 El Niño as an example. One of the areas that felt its impact the most was Santarém, a city in the Brazilian state of Pará, which experienced “a severe drought and extensive forest fires” that affected local wildlife, the team explains. The drought associated with El Niño impaired the forests’ ability to recover from these fires by affecting dung beetles. The species plays a key role in spreading seeds in the forest, and the dry conditions during the 2015-2016 El Niño caused their activity levels to plummet. Coral reefs were also critically damaged by the same El Niño, explains Professor Nick Graham from Lancaster University.

“The 2015-16 coral bleaching event was the worst ever recorded, with many locations globally losing vast tracts of valuable corals,” he explained.

“Worryingly, these global bleaching events are becoming more frequent due to the rise in ocean temperature from global warming.”

The team underlines that we need new conservation strategies to help ecosystems — especially rainforests and coral reefs — handle multiple, concurrent threats and that we need them fast. However, they also explain that local action may simply not be enough if we don’t tackle global climate change.

The paper “Climatic and local stressor interactions threaten tropical forests and coral reefs” has been published in the journal Philosophical Transactions of the Royal Society B: Biological Sciences.

In 2019, Brazil cut down twice as much of the Amazon as it did in the previous year

Deforestation in Brazil’s Amazon forest has risen by 104% compared to November of 2018, according to data released by Brazil‘s National Institute for Space Research (INPE) on Saturday.

Image credits Rosina Kaiser.

All in all, some 563 square kilometers (217 square miles) of forest were cut down in November, the largest area ever felled since November of 2015. It’s not only the sheer scale of deforestation that’s worrying, but also that it took part during the rainy season — when, traditionally, deforestation efforts slowed down.

A terrible toll

INPE’s report explains that between January and November of this year — which were the first 11 months in office for Jair Bolsonaro, a far-right leader who has eased restrictions on exploiting the Amazon — a total of 8,973.3 square kilometers (3464.6 sq mi) of the forest have been cut down.

That is almost double the total recorded over the first 11 months of 2018 (4,878.7 sq km).

The data was recorded by the DETER (Detecção de Desmatamento em Tempo Real), a satellite-based real-time deforestation detection system employed by INPE. The system uses data from the MODIS sensor aboard the Terra and Aqua NASA satellites. The system is mostly used as an indicator of the rate of deforestation but does not represent the whole area cut down, which is measured by the PRODES project.

According to PRODES readings — the system is more reliable but slower to compile data than DETER — between August 2018 and August 2019, the total deforested area in the Brazilian Amazon exceeded the 10,000 square kilometer threshold for the first time since 2008. It would represent a 43% increase over the preceding 12 month period (when the total was 7,033 sq km).

Areas of the Amazon that see indigenous habitation have experienced some of the fastest-rising rates of deforestation (74.5%) over the preceding period, INPE adds.

Ricardo Galvao, INPE’s former president, was sacked by the Bolsonaro government in early August under accusations of exaggerating the report on deforestation. On Friday, Galvao was named one of the 10 most important scientists of the year by the journal Nature.

The full report (link in Portuguese) can be read here.

Biochar could be key to rebuilding the Amazon forest

Credit: Wake Forest University.

Over the past few weeks, the world has witnessed in horror as the Amazon rainforest became engulfed in devastating fires. Besides fire, the Amazon’s iconic canopies are constantly being besieged by land clearing for agriculture, logging, and mining. However, scientists are researching ways to rebuild the rainforest.

Writing in a new study, researchers at Wake Forest University’s Center for Amazonian Scientific Innovation (CINCIA) found that biochar — charcoal used in soil amendment — is a cheap and effective material that can improve tree seedling survival during reforestation efforts.

The first few months following transplanting are the most vulnerable in a tree seedling’s life, but the researchers found that adding just a bit of biochar improves the soil, thereby improving the survivability of the seedlings. Adding fertilizers gives maximum results, the researchers found.

Biochar is beneficial for the soil, allowing it to retain more water and become less acidic. Biochar is also a great environment for microbes, which aid plant growth. Finally, biochar holds fertilizer and releases it over time. This winning combo decreases the need for repeat application of fertilizer, thereby lowering replanting costs.

For their study, the research team used soils from the San Jacinto native community in Peru, whose lands have been affected by gold mining. When the researchers led by Miles Silman analyzed this particular soil, they found that it was devoid of organic matter and microbes.

After adding biochar and fertilizers to two tropical tree species (Guazuma crinita and Terminalia amazonia) grown in the depleted soil, the researchers found that they could “fix” the damaged soil.

“We show that while both biochar and fertilizer can improve tree seedling growth, combining them makes seedlings thrive beyond either amendment alone,” said Silman.

The study suggests that biochar is excellent for recovering soil from areas damaged by gold mining.

“These are the kinds of landscapes we have to recover, and we are still trying to determine how to grow plants in them,” Silman said. “This soil is extremely limiting for natural regrowth, but treating them with biochar turns it into something that plants can grow in. That’s good for biodiversity and good for the people that have to make a living from the land.”

The findings appeared in the journal Forests.

Deforestation in Brazil continues to soar as current administration shows lack of interest

Deforestation in Brazil’s part of the Amazon basin has almost doubled in June compared to May — and May also had a higher-than-usual deforestation rate. This is largely attributed to the current administration reducing controls in the area which has emboldened loggers.

Logging in the Amazon. Image in public domain.

The Amazon basin is 20% larger than the entire European Union put together. It hosts the largest rainforest in the world, which has been teeming with biodiversity for 55 million years. The majority of the forest is contained within Brazil (60%) and has been continuously inhabited by humans for at least 11,000 years. With its over 400 billion trees, the Amazonian rainforest stores centuries worth of carbon, deflecting an important amount of solar heat. Around 20% of all the world’s freshwater cycles through this ecosystem, feeding its rivers, soil, plants, and animals. But, as we’ve known for quite a while, the rainforest is in trouble — and the current administration led by Jair Bolsonaro shows little intent to protect it.

Just minutes after he was sworn into office, Bolsonaro started an assault on Amazon rainforest protections, transferring the regulation and creation of indigenous reserves to the agriculture ministry, which is heavily influenced by agriculture industry lobby — the largest cause of deforestation in the area. His actions have emboldened loggers in the area. Although deforestation was temporarily stopped by a heavy rain season, things appear to be much worse than last year.

“Bolsonaro has aggravated the situation,” said Paulo Barreto, a researcher at Brazilian non-governmental organization Imazon.

In May, deforestation rose 34% compared to the same month last year, and in June clear cutting went up by 88%.

Deforestation is typically measured across an entire year to the end of July, but this year is already well on track to surpass its predecessor. Over the 11 months that have passed so far, there has been an increase of 4,565 square kilometers (1,762 square miles), with June alone exhibiting losses of 920 square kilometers.

Most of the area is converted into agricultural planting, particularly soybeans and grains. Ironically, this is largely fueled by the planet’s lust for meat, as most of these plants aren’t being used to feed people, but rather to feed cattle. Globally, 98% of soybeans are used to feed cattle, despite the fact that pound per pound, they have just as much protein as beef. Expanding ranches is also a driving force behind deforestation, as is the mining sector.

Claiming to boost economic growth, Bolsonaro has moved in to dismantle many environmental laws, as well as protections for the indigenous people. He has repeatedly spoken against environmental protections and “excessive” fines against logging. Along with his son, who is also a senator in the country, Bolsonaro is pushing to remove legislation that forces Amazon farmers to maintain a 20-80% tree cover.

The Amazon rainforest is vital for the global fight against climate change, making its protection a priority not only for Brazil, but for the entire world.

Rainforest canopy.

NASA creates first 3D model of Amazon rainforest canopy to estimate the effects of droughts, climate change

In an effort to estimate the effect of drought on the Brazilian Amazon, NASA has created the first ever 3D model of its canopy.

Rainforest canopy.

Image credits Robert Kerton / CSIRO.

Rainforests are some of the most complex and rich ecosystems on the planet (see here and here). One striking feature of such forests is that their canopies — which can rise up to 15 or even 20 stories high — form ecosystems unto themselves. However, they are in danger.

Climate projections suggest that the Amazon basin will experience warmer and drier conditions in the future. We’ve learned from periods of drought that rainforests don’t handle dryness well. When faced with long periods without rain, rainforest trees risk drying out because there’s not enough water in the soil for them to pump up to the canopies — so they starve.

However, we’re not quite at the point where we can estimate — based on our climate and precipitation projections — exactly how rainforests will react in the future. Simply put, estimating the number of dying or damaged trees (for example, where only branches are falling) is almost impossible. Rainforests are vibrant but chaotic, abundant but densely-packed places, and getting any kind of accurate data on tree health has long been an elusive goal for researchers.

When in doubt, LiDAR the sample

Traditionally, researchers attempted to record this data by hiking through rainforests and surveying a few acres of trees in spots along the way. They would count how many trees were alive, how many were dead, looked at the quantity and types of debris on the ground, and used these readings to estimate forest-wide averages.

Since that has traditionally not-worked-very-well, Doug Morton from NASA’s Goddard Space Flight Center in Greenbelt, Maryland, decided to use an eye in the sky. He and his team used an airplane-mounted light detection and ranging (LiDAR) device to create a 3D model of the Brazilian Amazonian canopy, drawing data from three separate flights in 2013, 2014 and 2016.

LiDAR works largely the same as radar, only it substitutes light in lieu of radio waves. Firing some 300,000 laser pulses a second, LiDAR can provide an incredibly detailed model of an object — much more accurate than what hiking researchers could achieve.

The team flew over two 30-mile (50 km) stretches near the city Santarém in the state of Pará, Brazil: one over the Tapajós National Forest (also in Brazil), and one over privately-owned stretches of the rainforest — most of which are strongly fragmented by human land-use. This region of the Amazon basin typically has a three-month dry season from October through December, the team writes, the same period when surface temperatures peak in the Pacific Ocean (during the El Niño event). El Niño delays the start of the rainy season in the central Amazon, leading to an extended dry season that stresses the trees.

The team used the LiDAR readings to detect gaps in the canopy — areas where a tree or branch had fallen in the months between each survey. They write that between 2013-2014 (a non-El Niño period), falling branches and trees altered around 1.8% of the forest canopy in the examined area. Scaled up over the whole Amazon basin, that would be equivalent to losing canopy trees or branches over 38,000 square miles (98,000 square km).

During the El Niño drought period from 2014 to 2016, branch morality rose by 65%, equivalent to 65,000 square miles (168,000 square km) over the whole basin.

Even subtle changes add up in the Amazon, Morton says, because it’s such a huge forest. So a subtle shift in precipitation patterns during an El Niño year ends up having a huge impact on the forest’s ability to sequester carbon. Dry periods, in other words, alters the balance between how much carbon the trees store as they grow versus how much they give off when they die and decompose.

However, the drought didn’t selectively affect more tall trees than smaller ones, as previous experiments suggest. This, Morton says, is good news.

“Large trees hold most of the carbon in any forest. If droughts were to preferentially kill large trees, it would boost the total amount of carbon that’s lost from drought as opposed to other disturbance types.”

The team says that understanding the effects of prolonged drought will give us a better sense of what might happen to atmospheric carbon levels if drought events become more common due to climate change.

The paper “El Niño drought increased canopy turnover in Amazon forests” has been published in the journal New Phytologist.

Tall trees in tropical forests are less vulnerable to drought

Photos from within the Amazon Rainforest in Tena, Ecuador. Credit: Jay, Flickr.

Photos from within the Amazon Rainforest in Tena, Ecuador. Credit: Jay, Flickr.

The Amazon rainforest is a huge carbon sink that, according to a 2017 study, absorbs as much carbon as all nine Amazon nations emit. Another study, however, discouragingly found that the amount of carbon the Amazon rainforest is able to absorb has declined by a third over the last decade. This decline is equivalent to over twice the UK’s annual emissions. This is partly due to the fact that the rainforest has reached a saturation point for how much carbon it can soak up, and partly due to droughts. But at least there’s some good news — according to a new study published today in Nature, taller trees in tropical forests are more resilient to droughts.

Not all trees convert solar radiation into chemical energy in the same way. Pierre Gentine, a researcher at Columbia University, New York, along with colleagues, found there is a great deal of variation in how tropical trees do photosynthesis. For instance, spatial and temporal patterns of photosynthesis in the Amazon are regulated by complex interactions between the climate, soils, nutrients and biotic factors. One other important factor that impacts photosynthesis seems to be height.

In order to understand how height affects photosynthesis in the Amazon forest, Gentine and colleagues analyzed remote sensing measurements of sun-induced fluorescence — an indicator of photosynthesis performance — as well as biophysical variables sourced from in-field and satellite measurements. The team found that taller forests are less sensitive to variations in precipitation than shorter ones.

Specifically, trees above 30 meters are three times less sensitive to drought than short trees under 20 meters. The scientists think this happens because taller trees have more extensive root systems that allow them to reach deep soil moisture during dry seasons.

However, taller forests are more vulnerable to atmospheric aridity. Leaves on tall trees constantly have a lower water content, making their photosynthesis not only more adaptable to soil drought but also more sensitive to fluctuations in atmospheric water.

The study’s results will prove useful in modeling climate change and performing conservation efforts aimed at mitigating climate change.

“[The findings] mean that the diversity in tropical forests is important to predict the response to droughts. We currently don’t represent this diversity in traits,” Gentine told ZME Science.

“We are now trying to see how forests are responding to droughts across the tropics,” he added.

Sunrise jungle Indonesia.

Hard-pressed by humans, rainforests lost their ability to act as carbon sinks

Rainforests are too degraded to act as carbon sinks any longer, a new paper reports. Averaged across the globe, rainforests now have a positive output of greenhouse gases, prompting the authors to call for urgent conservation efforts that will allow rainforests to re-don the mantle of carbon sinks.

Sunrise jungle Indonesia.

Image via Pixabay.

The team, composed of scientists at the Woods Hole Research Center and Boston University, took a different approach in assessing the health of rainforests. Unlike previous research, which generally focused on deforestation (complete removal of the forests), they worked to account for more subtle changes in the form of disturbance and degradation, both natural and anthropic. These changes include small-scale tree mortality or removal, or forest gains through natural or human-assisted growth.

Sadly, they report that when taking such changes in forest density into account, tropical forests lose their ability to act as net carbon sinks, meaning they emit more carbon that they can capture.

Net producers

The study quantified changes in aboveground forest carbon across tropical America, Africa, and Asia. These areas were selected as the sheer scale of their rainforests provide the greatest ability to act as carbon stores. They’re also the most biodiverse places on the planet, providing a wealth of ecosystem services such as food, fuel, and materials to millions of people — meaning they see a lot of human activity.

The team used 12 years’ worth of satellite imagery (taken between 2003-2014), laser remote sensing technology, and measurements taken in the field to calculate losses in forest carbon from flat-out deforestation as well as the more subtle and fine-grain degradation and disturbance processes, which have previously remained unaccounted-for over large swaths of rainforest. Their findings point to a worrying, death-by-a-thousand-cuts scenario playing out in Earth’s richest ecosystems.

Overall, tropical regions have become a net source of atmospheric carbon, they report. Forests saw an increase in capture power of roughly 437 teragrams of carbon annually (expressed as ‘carbon gains’), but losses amounted to a whopping 862 teragrams — meaning rainforests contribute a roughly 425 teragrams of atmospheric CO2 yearly. Each teragram is equivalent to one trillion grams, one million metric tons, or 1.102.331 short tons. To put that number into context, China and the US emitted some 10,600, respectively 5,100 teragrams of CO2 in 2015 (29.5% and 14.3% of world emissions).

“Gains result from forest growth; losses result from deforestation and from reductions in carbon density within standing forests (degradation/disturbance), with the latter accounting for 68.9% of overall losses,” the team writes.

“In many cases throughout the tropics you have selective logging, or smallholder farmers removing individual trees for fuel wood. These losses can be relatively small in any one place, but added up across large areas they become considerable,” said WHRC scientist Wayne Walker, one of the paper’s coauthors.

Losses and gains aren’t evenly distributed, however. On a by-continent basis, the majority of losses occurred in Latin America (some 60% of loss), in the Amazon forest. Some 24% of loss was seen in Africa, and Asia experienced the least share of total losses, with a little over 16%. Degradation and disturbance were responsible for the lion’s share of continental losses in both the Americas (70% of losses) and Africa (81%), but under half (46%) in Asia. Gains were also predominantly centered in the Americas with nearly 43% of total gains, followed by Africa with 30%, and lastly Asia with 26%.

Such results are worrying, especially at a time when governments around the world are scrambling to meet their commitments to the Paris Agreement and curb climate change. The authors note that ending deforestation, degradation, and disturbance in the tropics and allowing the ecosystem to regrow would cut at least 862 teragrams of carbon per year, some 8% of global emissions. The UN already has a project set in place to help preserve natural carbon sinks — the REDD+ (Reducing Emissions from Deforestation and Forest Degradation), which offers incentives for countries to maintain forests intact. However, it depends on regular access to accurate measurements of incremental gains and losses in forest carbon density, and research such as this one will give us a better understanding of how forests function.

“These findings provide the world with a wakeup call on forests,” said WHRC scientist Alessandro Baccini, the paper’s lead author. “If we’re to keep global temperatures from rising to dangerous levels, we need to drastically reduce emissions and greatly increase forests’ ability to absorb and store carbon.”

“Forests are the only carbon capture and storage ‘technology’ we have in our grasp that is safe, proven, inexpensive, immediately available at scale, and capable of providing beneficial ripple effects — from regulating rainfall patterns to providing livelihoods to indigenous communities.”

The paper “Tropical forests are a net carbon source based on aboveground measurements of gain and loss” has been published in the journal Science.

Every other day, a new species is discovered in the Amazon

Scientists have described 381 new species in the Amazon over a two-year period, while the rainforest is destroyed by relentless logging.

The Amazon stays true to its reputation as the world’s prime biodiversity hotspot. A new report by the WWF and Brazil’s Mamiraua Institute for Sustainable Development (link in Portuguese) indicates that in 2014 and 2015, no fewer than 381 have been discovered, more than one every two days.

Researchers discovered:

  • 216 previously unknown plants
  • 93 fish
  • 32 amphibians
  • 20 mammals
  • 19 reptiles
  • one bird

That so many species are continuously discovered is exciting and shows that we still have much more work to do before we can claim to understand the area. We’re still only scratching the surface when it comes to the wildlife living in the area. But we’re already destroying it.

Zimmerius chicomendesi, a newly discovered bird. Credits: WWF.

Bad news constantly flows from the Amazon and the findings also come with a dire warning: every single one of the newly discovered species was found in areas where mankind is threatening the forest. Ricardo Mello, co-ordinator of the WWF Brazil Amazon programme, commented:

“All the species that were discovered, all 381, are in areas where humankind is destroying the Amazon. This is very important to us, because it links the fact that our economic activities are causing species to go extinct before we even know about them,” he said.”

Sarah Hutchison, WWF’s head of programmes for Brazil and Amazon, was even blunter. She points out that there are many species which we may kill off before we even get a chance to discover them — and many we might have already killed off.

“We are only at the tip of the iceberg when it comes to unveiling the incredible species that live in the Amazon, yet instead of this precious area being safeguarded, it is under greater threat than ever before.

“The discovery of 381 new species is a wake-up call for the governments of Amazon countries that they must halt the ongoing and relentless deforestation and work to preserve its unparalleled biodiversity. If they don’t, there will continue to be irreversible impacts on the Amazon’s much-loved wildlife, undiscovered species and the local and indigenous people that call it home.”

But there is still hope. She says that this report and other studies like it will serve as a wake-up call. More than 2,000 new species were found between 1999 and 2015. Identifying a species is only the first step. We still need to understand how the species interacts with its environment, and how we can better protect them.

For instance, the pink river dolphin is under threat from the construction of hydroelectric dams as well as industrial and agricultural activity. The fire-tailed titi monkey is under threat from deforestation — like many other creatures.

Unfortunately, science is also another step along the conservation ladder. Scientists do their job, but there is no guarantee that policy makers will listen, and even if they do, conservation measures have proven notoriously difficult to enforce along the Amazon.

Norway to Brazil: If you keep destroying the Amazon, we’ll cut our $1bn funding

Since 2008, Norway has been offering financial support to Brazil (over $1.1 bn), in order for the latter country to preserve its rainforests and fight deforestation. Amidst rampant corruption, an impeached president, and a clear divide between what people want and what politicians want, the country seems unable (or unwilling) to respect its commitment. In response, Norway issued a blunt warning: stop what you’re doing and fast, or we’ll cut off the money.

Aerial view of the Amazon Rainforest, near Manaus, the capital of the Brazilian state of Amazonas. Image credits: Neil Palmer.

The Scandinavian country committed to efforts not only to reduce its own carbon footprint but also to make an external, international contribution; and it works. Although deforestation in Brazil is at alarming levels, it’s much lower than the 19,000 sq km of cleared rainforest seen in 2005 alone. For a time, deforestation rates were going lower and lower, but now, they are on the rise again.

In a forthright letter to Brazil’s environment minister, José Sarney Filho, seen and quoted by the Guardian, Vidar Helgesen, Norway’s environment minister, expressed his concerns. Helgesen went further, saying that if trends continue, Norway will cut the funding.

“In 2015 and 2016 deforestation in the Brazilian Amazon saw a worrying upward trend.” He warned that this had already reduced Norway’s contributions and added: “Even a fairly modest further increase would take this number to zero,” Helgesen wrote.

At the core of this problem lies the fact that Brazilian authorities removed protection from large areas of the Amazon, weakening the licensing required for deforestation and agricultural implementation in rainforest environments. These issues are tightly connected with corruption scandals, bribes, and the threatening (sometimes killing) of indigenous people.

Annual deforestation in Brazil jumped by 29% to 8,000 sq km in 2016, dangerously close to the 8,500 sq km limit agreed by Brazil and Norway. Norwegian concerns are easy to understand — if the trends from past two years continue, the limit will certainly be crossed. The budgetary cuts to the environment ministry and other departments that protect the Amazon add even more reasons to worry.

Sometimes referred to as the “lungs” of the earth, the Amazon’s 390 billion trees absorb 1.5 gigatons of carbon dioxide a year; they also host the world’s largest biodiversity hotspot. This entire basin encompasses 7,000,000 square kilometres (2,700,000 sq mi), of which 5,500,000 square kilometres (2,100,000 sq mi) are covered by the rainforest. Not all of it is in Brazil — the country hosts 60% of the rainforest, giving it the largest responsibility.

The forests won’t fix our CO2 problem — in fact, they’ll scrub less than we assumed

Carbon dioxide absorption by growing biosphere may have been overestimated up to now, a new study concludes. This is due to previous estimates not taking into account the limiting factor of essential nutrients on plant development.

Image via Pixabay.

One effect of rising concentrations of CO2 in our atmosphere is that plants have more of the gas — a prime source of carbon — to metabolize, improving growth rates. It also raises average temperatures in cold areas, promoting plant growth. Satellite imagery has shown that while growth has declined in some areas, our planet is getting greener overall.

Climate scientists have pointed out that this increased quantity of plants will be able to scrub even more CO2 out of the atmosphere, forming a natural carbon sink, and helping mitigate our emissions. But they have overestimated just how much the biosphere will grow, and thus how much more carbon it will soak. By testing the effect of higher CO2 levels on forests growing in tropical and subtropical soils, a team from the Western Sydney University in Australia has found that the biosphere will likely grow less than what previous estimates have projected.

Plenty of carbon, scarce phosphorus

The team, led by David Ellsworth of Western Sydney University in Australia, says that forests will absorb around a tenth less CO2 than previously expected, meaning CO2 levels will rise even faster than our current models predict. The main limiting factor opposing CO2’s fertilizing effect is the lack of phosphorous in tropical and subtropical regions, they explain.

To determine how much the biosphere will grow, the team artificially raised CO2 levels in six plots of a mature eucalyptus forest near Sydney, which were growing in characteristically phosphorus-poor soil. The plots were covered in a mix of individuals of diverse species and ages.

Previous similar work in temperate forests (whose soils are much richer in phosphorus) found that CO2 increase could boost growth by as much as 20%. Ellsworth’s team found no evidence of growth boost in their plots at all. They attribute this difference to the limiting effect of phosphorous (a key nutrient) on growth. The results are backed by previous results, showing plant growth in the past 30 years didn’t see as much an increase as we estimated.

Another (very) limiting factor is human activity. Although some forests will grow faster if left to their own devices, we have a pretty consistent habit of cutting them down. Martin Brandt et al. show that while there’s overall more woody vegetation in Africa, the effects of warmer climate and rising levels of CO2 are offset by deforestation for raw materials and arable land in highly populated, humid areas, leading to a decrease in woody vegetation for these regions. The biggest increase in forests was seen in dry areas with low human populations, but it’s unclear if this makes up for the losses in vegetation elsewhere.

Ellsworth also points out that an increase in plant growth doesn’t necessarily translate to an increase in CO2 absorption and storage by plants.

Where does this leave us? Well, while it would be a nice turn of events it seems unlikely that the trees will clean our mess. So overall the situation takes a turn for the worse. Our best bet, as up to now, is to limit emissions and find ways to sequester CO2. In the meantime, we should also try as much as possible to mitigate the damage.

The full paper “Elevated CO2 does not increase eucalypt forest productivity on a low-phosphorus soil” has been published in the journal Nature Climate Change.


The Atlantic Forest is now designated a World Biosphere Reserve, which contains a large number of highly endangered species.

When humans hunt large animals, they’re literally killing the forest too

It’s the bigger or charismatic of animals that get targeted by human hunters. These give off more meat, more pelt and make for better trophies. The effects of over-hunting and poaching are well documented. Most markedly, this results in extinction and ecosystem destabilization. A new study, however, adds a new frighting dimension to hunting: climate change acceleration through loss of carbon storage.

The Atlantic Forest is now designated a World Biosphere Reserve, which contains a large number of highly endangered species.

The Atlantic Forest is now designated a World Biosphere Reserve, which contains a large number of highly endangered species.

The world’s forests act like carbon sinks, sucking up much of the excess carbon from the air while providing fresh O2 in the process. Tree store this carbon keeping it from warming the planet. Naturally, deforestation will mean that this carbon storage capability will be reduced, with global warming as a direct consequence. But killing animals can be just as damaging to the ecosystem as cutting down trees, a new study made by Brazilian researchers suggests.

Frugivores – animals who eat fruit – are considered to be important seed disperses for many tropical plant species. Seed and/or fruit size limits the number of frugivores that can disperse the seeds and, in general, large frugivores can handle a wider range of fruit sizes than small frugivores. These large frugivores are thought to be vulnerable to extinction in the face of selective hunting and habitat loss and degradation . Therefore, plants that produce large-sized fruits and/or seeds may be vulnerable to extinction when they lose their natural seed dispersers.

The researchers devised an ecological model using data gathered by extensive surveys across the Atlantic Forest of Brazil — the second largest rainforest in South America, but also one of the most devastated wood covered regions in the world by deforestation. “When you land in Rio de Janeiro, for instance, you are landing in the Atlantic forest,” says Mauro Galetti, one of the study’s authors and also based at the Universidade Estadual Paulista. “But only 12 percent of this forest is left, it was destroyed in the last 500 years.”

The original size of the Atlantic Rainforest once covered over 1.23 million km2. Today a mere of 99 thousand km2 remain. That is less then 7%!

The original size of the Atlantic Rainforest once covered over 1.23 million km2. Today a mere of 99 thousand km2 remain.

The analysis suggests that without large frugivores like tapirs, spider monkeys, toucans and agoutis, the rain forest would look strikingly different. The diversity in tree species plummets. A more densely packed forest, but with much smaller trees (an proportionally smaller carbon sequestration value) takes its place since these bear smaller seeds which are dispersed by bats, birds and small marsupials (not hunters’ favorite).



Credit: Mauro Galetti



Credit: Mauro Galetti

Their work shows a close relationship between large fruit-eating vertebrate animals and the tallest trees, and the researchers claim this analysis should apply to all of South America’s rainforests – not just the Atlantic Forest.

“Halting the ongoing, fast-paced defaunation of tropical forests will not only save large charismatic animals and the plants they disperse but also have effects on climate change, carbon markets, and reforestation processes,” the authors conclude.

Most climate change discussions revolve around carbon, trees and the oceans. Maybe it’s time animals get included as well. Their contributions surely warrant serious consideration.

amazon rainforest

Half of Amazon rainforest tree species threatened by deforestation

The Amazon basin is home to the world’s greatest biodiversity. You’ll find more plant and animal species per square foot than anywhere else in the world. It’s truly one of the wildest and life teeming places in the universe, which given humans’ habit of meddling makes it one of the most vulnerable as well. The huge 6-million-square-kilometer rainforest area remains mostly unstudied, due to the roughness and inaccessibility of the land. But making their way through the outskirts are the chainsaws and sawmills; and they’re moving fast. Since 2000 an area equal to 50 football pitches has been destroyed every minute in the Amazon rainforest, satellite imagery revealed.

amazon rainforest

The environmental consequences are stark. The Amazon rainforest acts like a huge carbon sink, and destroying it will cause more carbon emissions to stay in the atmosphere, further warming the planet. Loss of habitat will force many species of animals into extinction, but also tree species themselves. Scientists estimate that there are between 11,000 and 15,000 tree species in the Amazon and deforestation could threatened more than half of them, according to massive field study which involved  160 botanists, ecologists, and taxonomists from 97 institutions.

Researchers surveyed 1,485 sites in the Amazon basin and identified  4,953 tree species. Using a biodiversity model, the researchers inferred that there must be another 10,000 tree species, especially towards the isolated center where few humans reside, but vegetation is very dense. The maps were then compared to deforestation maps to assess how tree species might be threatened under two scenarios: business as usual (deforestation continues unabated at its current pace) and an Amazon friendly scenario, in which government and corporations work together to steadily stop logging.

If the status quo is preserved, 51 percent of the Amazon’s common tree species’ populations and 43 percent of rare tree species’ populations would decline by 30 percent or more. That’s enough for them to be included in the  International Union for Conservation of Nature‘s “Red List” of threatened species. Even under the less severe scenario, 16 percent of common species and 25 percent of rare species will qualify under the ‘Red List’. ‘

“We overlay spatial distribution models with historical and projected deforestation to show that at least 36% and up to 57% of all Amazonian tree species are likely to qualify as globally threatened under International Union for Conservation of Nature (IUCN) Red List criteria. If confirmed, these results would increase the number of threatened plant species on Earth by 22%,” the researchers conclude in the study’s abstract.

Remember, the Amazon basin is home to:

  • 1/3 of the world’s species;
  • 1/4 of the world’s freshwater;
  • 1/5 of the world’s forests;
  • 48 billion tons of carbon dioxide in its trees;
  • 200 indigenous and traditional communities.

It’s paradise on Earth, yet we’re destroying the rainforest bit by bit. Luckily, there is hope. Things are changing. In Brazil,  the deforestation rate last year was roughly 75% below the average for 1996 to 2005, thanks to commendable efforts from behalf of the government. Brazil’s experience suggests that humanity has a chance to control agricultural expansion and preserve the planet’s most diverse ecosystems.



The Number of Trees has Halved Since Human Civilization Emerged

Today, the Earth has approximately 3 trillion trees left standing – about 422 per person – but we’ve already cut 46% of them.

Branching out


Using a mixture of satellite imagery, forest inventories and supercomputer technologies, an international team led by Yale researchers conducted the biggest survey ever on trees, mapping them globally at a square kilometer level. The researchers also used projected maps of current and historic forest cover, which were provided by the United Nations Environment Programme to see how much tree loss has occurred over time. Their results showed that there are more trees on Earth than was previously estimated, but we’ve still destroyed a big chunk of total trees: almost half. That’s already starting to take its toll.

“We have nearly halved the number of trees on the planet and we have seen the impacts on climate and human health as a result,” said Thomas Crowther, post-doctoral fellow at Yale University’s school of forestry and environmental studies (F&ES) and lead author of the study.

Indeed, we generally take trees as granted, and we often forget just how important their are for the planet – not just in terms of biodiversity, but in terms of climate, soil stability and many others. The environmental services that trees provide are inestimable.

“They store huge amounts of carbon, are essential for the cycling of nutrients, for water and air quality, and for countless human services. Yet you ask people to estimate, within an order of magnitude, how many trees there are and they don’t know where to begin,” he said, adding he was “certainly surprised” to find the estimate was in the trillions. Trees are among the most prominent and critical organisms on Earth yet we are only recently beginning to comprehend their global extent and distribution,” Crowther added.



Tree populations have remained relatively stable and constant before the human effect started kicking in. We’ve been cutting trees at an enormous rate, especially in areas like the Amazon forests in South America, but many forests in Asia, Europe and North America have also been decimated.

Trees and humans

To say that there are 422 trees per person on Earth is, while true, pretty misleading. The tree density varies greatly across continents and even countries, with the highest tree densities in the sub-arctic regions of Russia, Scandinavia and North America. In terms of total tree cover, South America still reigned supreme though, home to 43% of the world’s trees. In the UK for example, researchers found more than three billion trees, or around 47 per person, while in Ireland there are some 709 million trees, or 154 per person. That means that the trees/person rate in the UK is 10 times lower than the global average, and similar figures are reported for most of the developed world.

“The diverse array of data available today allowed us to build predictive models to estimate the number of trees at each location around the globe,” said postdoctoral student Henry Glick.

The census won’t just help us understand how many trees there are in the world, but inform scientists about the structure of forest ecosystems in different regions and calculate the amount of damage we’ve already done – and what we should do if we want to repair it; essentially, we are now the main driver controlling tree spread and density.

“The scale of human impact is astonishing,” says Thomas Crowther, an ecologist now at the Netherlands Institute of Ecology in Wageningen who led the study while at Yale University in New Haven, Connecticut. “Obviously we expected humans would have a prominent role, but I didn’t expect that it would come out as the as the strongest control on tree density.”


The most worrying fact is that we’ve been stunting tree development especially in places where we’d expect them to thrive – in warm, moist regions. Farming and deforestation often go hand in hand, as do deforestation and ecosystem destruction. The effects of cutting down trees and forests are long reaching and difficult to grasp, but one thing’s for sure: if we continue with the ‘business as usual model’, we’re going to be doing irreparable damage, and everyone on this planet, including us, will have to pay.

Journal Reference: Crowther, T. W. et al. Nature http://dx.doi.org/10.1038/nature14967 (2015).

Seven new species of frogs discovered – they’re tiny, and they’re adorable

Seven miniature species of frogs living on seven different mountain tops sounds like the premise for the next Kung Fu Panda sequel. But as researcher Marcio Pie of the Federal University of Parana and his colleagues show in a paper published in PeerJ., it is what they have found in the Atlantic Rainforest of Brazil. Measuring under a centimeter in length on average, the miniature members of the frog genus Brachycephalus like to keep to their own confined territories and have evolved into many varied, but hard to find, species.

Brachycephalus verrucosus has orange-hued skin covered with brownish-green bumps.
Image via: www.washingtonpost.com/

Marcio and his colleagues had to trek up small but rugged mountains, many of which lack well-marked trails to find the little frogs. Given that the area is so rich in these tiny amphibians and since each species holds to one mountain top, it’s assumed that each new mountain searched will yield a new species. If we can catch them.

“It takes a lot of practice and sometimes it’s very frustrating, to go up the mountain for many hours and come back empty-handed,” Pie told the BBC. “You can hear them singing and there’s probably hundreds of them, but you simply can’t catch them! Because once you get closer, just from the vibration in the ground, they keep silent for, say, 20 minutes or half an hour. And then you have to go through the leaf litter very carefully with your hands,” he said.

The main characteristics differentiating between the frogs, many of which have fewer fingers and toes than most in order to optimize for their size, is skin color and texture. They produce varying levels of a neurotoxin called tetrodoxin for self-defence, and their bright skin colors are a warning to potential predators.

“Don’t-eat-me-orange” is hot frog fashion in Brazil.
Image via: www.livescience.com

But it is their exclusive habitat, not predators, that gives Pie ground for concern. He and his colleagues warn that the frogs are in danger of extinction:

“The species is known from a restricted area that is under a variety of sources of perturbation, including deforestation, fire, and cattle farming—even though it theoretically should have been protected given its current status as a private reserve (“Reserva Particular do Patrimônio Natural”). Therefore, the conservation of this locality is necessary for the survival of this species.” they remark in their paper.

Logging and climate change pose serious threats to the tiny frogs’ survival. They are very sensitive to temperature, this being the main reason they never expanded their territory beyond the mountain tops. To ensure their survival, we may need to start raising them in captivity, say the researchers.

Dust from the Sahara Desert Fertilizes the Amazon’s Forests

The Sahara Desert and the Amazon area have few things in common – one is a dry, barren wasteland, while the other is the most fertile area on Earth. But according to a new NASA study, there may be more than meets the eye when it comes to the two – dust from the Saharan area makes the trans-Atlantic journey, fertilizing the Amazonian rainforest with phosphorus.

The Sahara Desert actually “sends” dust to the Amazon rainforest, via global winds. Image via Wiki Commons.

Sahara is basically an uninterrupted brown band of sand stretching across the entire northern Africa. The Amazon rainforest covers 5,500,000 square kilometres of rainforest in South America, representing over half of the planet’s remaining rainforests, and comprising the largest and most biodiverse environment in the world. But strong winds connect the two areas – the winds sweep across the Sahara, rising dust particles in the air and bringing them all the way to the Amazon, where they help make the area even more fertile with the embedded phosphorous.

A new paper published in Geophysical Research Letters, a journal of the American Geophysical Union, provides the first description of how this happens. Hongbin Yu, associate research scientist at the Earth System Science Interdisciplinary Center (ESSIC) at the University of Maryland and his team estimated how this phosphorous affects the rainforest. In January, he and his team already published a paper which used satellite data to see how much sand reaches the Amazon. Using data collected by a lidar instrument on NASA’s Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite from 2007 through 2013, the team estimates that roughly 22,000 tons of phosphorus make the trans-Atlantic journey each year – that’s very similar to the quantity of phosphorous lost through flooding and water runoff.

This is very important because nutrients, like the ones found in commercial fertilizers, come in short supply in the Amazon – because they are locked in the plants themselves. While decomposing leaves for example do provide nutrients to the soil, phosphorous is generally washed away by rainfall into streams and rivers. In a way, the Amazon basin acts like a “giant leaky bathtub”.

This is where the dust steps in, to compensate that deficit – and it also has an impact on the climate.

“We know that dust is very important in many ways. It is an essential component of the Earth system. Dust will affect climate and, at the same time, climate change will affect dust,” said Yu in a recent statement.

The lidar instrument aboard the CALIPSO satellite sends out pulses of light that bounce off particles in the atmosphere and back to the satellite. It distinguishes dust from other particles based on optical properties.
Image Credit: NASA Goddard’s Scientific Visualization Studio

The data showed that wind and weather pick up on average 182 million tons of dust each year and carry it past the western edge of the Sahara – that’s the equivalent of almost 700,000 trucks filled with sand. 132 million tons remain in the air, while 27.7 million tons (the equivalent of over 100,000 trucks) reach the Amazon. Most of that is phosphorous. What’s interesting is that 43 million tons of dust travel farther to settle out over the Caribbean Sea, in Central America.

Researchers underline the fact that this dust might have a huge impact on the climate and nutrient cycle of many areas, due to the huge quantities involved. However, we can’t establish long term trends based on only this seven year observation, so we need to pay more attention to this cycle, over a longer period of time.

“We need a record of measurements to understand whether or not there is a fairly robust, fairly consistent pattern to this aerosol transport,” he said.

Even within this period, there was significant variation – there was an 86 percent change between the highest amount of dust transported in 2007 and the lowest in 2011, Yu said. It’s not clear why this happens, nor is it clear what impact the dust has on a larger scale, in terms of affecting the climate. But knowing that the Amazonian forest and the Caribbean is affected by something as remote as the Sahara desert is definitely exciting.

“This is a small world,” Yu said, “and we’re all connected together.”