Tag Archives: global heating

Earth’s carbon dioxide levels hasn’t been this high in mankind’s entire history

Carbon dioxide levels have hit an all-time high — again. In May (the month scientists use to compare year-to-year CO2 shifts), carbon dioxide in the atmosphere averaged 419 parts per million, according to data from Scripps Institution of Oceanography and the National Oceanic and Atmospheric Administration (NOAA). 

Unfortunately, that in itself would hardly even classify as news anymore. But what really is striking is that CO2 levels haven’t been this high since before humans emerged as a species. We’d have to go to the Pliocene Epoch, between 4.1 to 4.5 million years ago, to see similar levels — a period when sea levels were nearly 80 feet higher and temperatures were about 7°F above the preindustrial era.

Not even a pandemic that kept many of us inside could stop the rise of atmospheric carbon dioxide. The long-lived greenhouse gas driving climate change has fluctuated naturally throughout our planet’s history, but scientists are virtually certain that the current accumulation is driven by human activities — especially the burning of fossil fuels. It’s a clear sign that the world is not doing nearly enough to curb emissions.

“The ultimate control knob on atmospheric CO2 is fossil-fuel emissions,” Scripps Oceanography geochemist Ralph Keeling said in a NOAA statement. “We ultimately need cuts that are much larger and sustained longer than the COVID-related shutdowns of 2020.”

It’s not just that CO2 levels are increasing, but the pace at which they are rising is alarming. In 2013, the world first passed a historic mark: 400 parts per million (ppm) of CO2 in the atmosphere. Since then, it took just eight years to climb to 420 ppm, and now, we’re already at 429 ppm.

Initially, there were hopes that the pandemic would at least slow down greenhouse gas emissions — and for the first part of the year, that was true. But by the end of 2020, it was almost as if nothing had changed. Emissions in the last months of the year were already higher than the ones in previous years.

The past year also marked the five-year anniversary of the adoption of the historic Paris climate agreement. Within the plan, countries agreed to take action to reduce their emissions and keep the planet in line with a warming of no more than 2 degrees Celsius over pre-industrial levels (and the ambitious goal of 1.5 Celsius). With temperatures already over 1 degree Celsius over pre-industrial level, the ambitious goal is all but gone now — and even the “normal” goal seems questionable, as few countries have backed up their declared ambitions with action.

CO2 emissions can last for 1,000 years in the atmosphere, and as long as we keep emitting the gas, it will continue to accumulate. Global emissions have likely not peaked, and will continue to drive climate change to uncharted and dangerous territory. Climate change is already costing the world in the trillions, and the cost is only expected to rise as emissions ramp up.

A deep look at carbon capture and storage (CCS) and its role in the climate crisis

Carbon Capture and Storage (CCS) is the process of capturing carbon dioxide (CO2), a greenhouse gas, and depositing it somewhere it will not reach the atmosphere again — typically in a suitable geological formation. The goal is to reduce the amount of greenhouse gases in the atmosphere and limit (or even reverse) man-made climate heating.

Does it work?

It’s not science fiction. The technology already exists and several projects are already underway. The carbon dioxide is typically extracted from a single point source (like a cement factory or a fossil fuel facility), and injected into a porous structure where the CO2 can be absorbed without leaking back into the atmosphere. Carbon dioxide can also be absorbed from the air, although the efficacy of this process is much lower.

Carbon capture and storage can reduce the emissions of a plant by up to 90% and when coupled with other technologies, CCS can even lead to negative emissions.

The technology is regarded by many researchers as a key tool in our fight against global warming and greenhouse gas emissions as it is not only a way to reduce our emissions, but maybe even to grab some of the greenhouse gases already present in the atmosphere and store them. However, CCS comes in many different forms and, at this moment, there are only a handful of operating CCS projects in the world.

Simply put, it works — the physics of the process is valid. But whether or not CCS will really be used on a wide scale and help us keep climate change in check is a very different question.


The planet is heating up. Over the past century, the planet’s average surface temperature has risen by about 2 degrees Fahrenheit (a bit over 1 degree Celsius) — a change driven largely by increased carbon dioxide and other man-made emissions into the atmosphere.

We won’t get into the details of how we know climate change is happening and that it’s caused by mankind. All the available figures and scientific evidence point in this direction. Greenhouse gas emissions have increased steadily since 1890, and as a result, temperatures are rising. The problem is very real and burying our head in the sand won’t help one bit.

If we want to truly manage this crisis, we need to reduce our emissions, achieve net zero emissions, and, ultimately, find ways to revert previous emissions. The good news is that CCS can help with both.

Right now, society most focused on producing renewable energy to replace polluting and carbon-intensive fossil fuels. In truth, it’s not just just the environmental aspect of it, renewable energy is already cheaper in many parts of the world (but that’s a different story). Important as this may be, it’s not enough on its own.

A substantial part of our emissions comes from other industrial activities (like cement factories, for instance) which are extremely hard to decarbonize, and it’s not like all fossil fuel power plants will disappear overnight — we need to reduce emissions from them in the meantime. This is where CCS can come in and make a difference.

However, we can’t just capture carbon dioxide, put it in a box and wash our hands, it just doesn’t work that way. You can’t build a carbon storage factory. Luckily enough though, nature has done that herself.

Geology to the rescue

Some subsurface geological features are excellently suited as carbon storage sites. Some brine-filled pores in sandstone formations, or other similar structures sealed by a natural and impermeable caprock such as a shale or clay. Essentially, you need a porous rock to inject the carbon in, and impermeable rocks to act as a seal around it.

In some contexts, carbon storage has been used for several decades (most notably for enhanced oil recovery), but as a tool to tackle global heating, it’s a relatively new concept. For many current CCS projects, the technology used to lock CO₂ deep underground is the same technology used to enhance oil reservoirs. In one oil field (called Sleipnir), some 23 million tons of CO₂ have been injected underground. In the case of Sleipnir, the positive effect of injecting CO₂ is counterbalanced by the extraction (and subsequent burning) of oil. But what if we could just have the positive effect and not do the oil part? That’s pretty much how the idea of carbon storage emerged.

It’s been actively researched in the US since 1997, but the technology first took off in Norway in the 1980s. Although the basic principle is still the same, CCS as a field of science has grown and developed massively since. CCS publications and studies have increased exponentially in the past 20 years, with international collaboration spurring multiple projects. Still, as of 2019, there are only 17 operating CCS projects in the world, capturing 31.5Mt of CO₂ per year, of which just 3.7 is stored geologically. Compare that to the 5.1 billion metric tons of energy-related carbon dioxide the US emitted in 2019 alone — it takes the US just a couple of days to emit more CO₂than is stored year-round in the entire world.

But this doesn’t mean that CCS can’t grow. The latest IPCC Assessment Report on Mitigation mentioned CCS 35 times in the summary for policymakers. The International Energy Agency has repeatedly said CCS is a key technology for mitigating climate change. More and more, researchers are looking at CCS as one of the key ways to address some parts of our greenhouse gas emissions.

At the very least, the geological potential is there. The US National Energy Technology Laboratory (NETL) reported that North America has enough storage capacity for more than 900 years worth of carbon dioxide at current production rates. Even though there is some uncertainty regarding potential long-term leaking, there’s still more than enough room for the world to dump its carbon underground.

Location, location, location (and technology)

Carbon capture and storage is most effective when it’s applied at point sources such as a single factory or a single storage site — it’s far less effective when dealing with multiple, smaller sources. This is what makes it an excellent technology for heavy-emission industries.

Exasmple of how CCS can work at a biomass plant. Image credits: Wiki Commons.

There are three main types of carbon capture and storage for industrial facilities:

  • post-combustion capture is the most widely used form of carbon capture and storage. It essentially refers to capturing CO₂ from a flue gas generated after combusting a carbon-based fuel, such as coal or natural gas. A number of different techniques are used ,and post-combustion capture is especially interesting for researchers because existing fossil fuel power plants can be retrofitted to include CCS technology in this configuration.
  • pre-combustion capture is widely applied in fertilizers, gaseous fuel (H2, CH4), and power production. The advantage is you also obtain hydrogen which can be used as a fuel. However, retrofitting plants to accommodate pre-combustion capture is challenging and this is mostly an option for new plants.
  • oxy-fuel combustion, where the fuel is burned in oxygen instead of air. This results in a flue gas that is mainly CO₂ and water.

There are multiple technologies for separating CO2, becoming more and more efficient every year. But after it’s separated, the CO2 must be transported. This is most easily done via pipes (and has been done before). For instance, there were approximately 5,800 km of CO2 pipelines in the United States in 2008, and a 160 km pipeline in Norway used for enhanced oil recovery.

After it’s separated and transported, it is injected into a suitable geological reservoir.

Negative emissions — taking carbon from the atmosphere

So far, we’ve mostly focused on using CCS for factories, as a way to reduce emissions. But CCS can also be used as a way to revert emissions — or, as researchers put it, to produce negative emissions.

Cement amounts for about 8% of the world’s greenhouse gas emissions. Image credits: Kåre Helge Karstensen, SINTEF.

The underlying principle is straightforward: you extract carbon from sources in the Earth’s biological cycle and inject them on the ground. This way, you’re not just reducing the carbon you’re outputting, you’re essentially eliminating some of the already existing carbon. So you would take something like wood chips or biological waste such as manure and inject the carbon from it to a geological storage site.

But it can get even more interesting than that. In a recent study, researchers discovered a way to pull carbon dioxide from the atmosphere and turn it back into coal. This approach is actively being researched by fossil fuel companies, who are looking for a way to maximize returns. However, in order for this to truly have a net positive effect, the subsequent burning of the resulting coal would also have to be captured.

Perhaps the most exciting development comes from Iceland, where researchers found a way to extract CO2 and mineralize it into rocks. They’ve essentially created ‘negative emissions plant’ — a plant that turns ambient CO2 into stone switches.

Iceland’s large basaltic fields could be a boon for CCS. Image via Unsplash.

The key to rapid mineralization of carbon is basalt – a volcanic rock which Iceland has an abundance of. Iceland is actually mostly made up of basalt (90%), and within basalt, CO2 can quickly mineralize (morph into carbonate rocks). “The potential of scaling-up our technology in combination with CO2 storage, is enormous,” said Christoph Gebald, the founder and CEO of Climeworks, the company behind the technology.

But for all these exciting developments, there’s one part we’ve purposely left out until now: money.

Without a carbon tax, CCS just won’t work

What about the money? As we’ve seen in the case of renewable energy, green technologies can only truly succeed when they have at least some economic advantage. Separating CO₂ from other chemicals is costly and also requires energy. But unlike renewable energy, in the case of CCS, there’s no real economic advantage — all you have is a method of reducing CO₂ emissions, that’s it.

At the moment, even as CCS is making great strides in terms of technology and research, the funding for said technologies is starting to shrink. This is a problem not just for carbon storage, but for our ability to meet current climate commitments and avoid catastrophic environmental and economic damage.

Nowadays, CCS projects rely on government incentives and standards — even though economists generally agree that these programs are less effective and more costly than a carbon price. Carbon pricing is notoriously unpopular and hotly debated, but increasingly, leading economists are calling for some sort of a climate tax. Without such a tax (or some pricing mechanism), CCS remains a niche technology and is unlikely to scale massively into the future.

“I prefer to have an economy-wide carbon price to create markets for low-carbon technology. Then markets, not advocates, will make decisions about the technology mix. I believe deployment of CCS would be significant under such a policy,” writes Howard J. Herzog Senior Research Engineer, Massachusetts Institute of Technology.

Simply put, new policies are dearly needed to incentivize commercial CCS. No matter how you look at things reaching net-zero emissions (and maybe, someday even negative emissions) seems much harder without CCS — but without financial incentives CCS cannot flourish, even when the technology matures. A University of Warwick report concludes:

“CCS has considerable potential to reduce CO2 emissions not only by a significant amount but also at a social cost that most economists would not consider prohibitive, particularly in comparison to the social costs predicted for a business-as-usual scenario with unregulated carbon emissions.”

The planet got warmer last year due to fewer aerosol emissions

Things are not always clear and straightforward when it comes to global temperatures. Despite fewer emissions last year, temperatures were up between 0.1ºC and 0.3ºC during the spring, especially in the United States and Russia.

Image credit: Flickr / UN

Emissions of greenhouse gases such as carbon dioxide (CO2) warm the planet over time, trapping heat in the atmosphere. But that’s not the case with aerosols. Aerosols are formed during combustion and make clouds brighter to reflect sunlight away from the earth. Fewer aerosols mean less of that cooling effect, leading to a warmer Earth.

“There was a big decline in emissions from the most polluting industries, and that had immediate, short-term effects on temperatures,” Andrew Gettelman, the study’s lead author from the National Center for Atmospheric Research (NCAR), said in a statement. “Pollution cools the planet, so it makes sense that pollution reductions would warm the planet.”

Looking at last year’s pollutants most closely, Gettelman and other researchers at NCAR found that the drop in aerosols last spring allowed more of the Sun’s warmth to reach the planet. This was especially the case in industrialized countries, which usually release a lot of aerosols into the atmosphere.

Temperatures over parts of the planet’s land surface last spring were between 0.1ºC and 0.3ºC warmer than expected, considering the prevailing weather at the time, the study showed. The effect was particularly significant in the United States and Russia, where temperatures were 0.3ºC above expected over much of the territory.

Scientists have long been able to quantify the climate impacts of CO2 and other greenhouse gases. This hasn’t been the case with aerosols such as sulfates, nitrates, black carbon, and dust. Projecting the extent of future climate change requires estimating the extent to which countries continue to emit aerosols in the future and the influence they have on clouds.

For their research, Gettelman and his team used two climate models: the NCAR-based Community Earth System Model and a model known as ECHAM-HAMMOZ, developed by a consortium of European nations. They did simulations on both models, adjusting emissions of aerosols and incorporating meteorological conditions in 2020.

Not a call for more pollution

While the study illustrates how aerosols can counter the warming influence of greenhouse gases, emitting more of them into the lower atmosphere isn’t a viable strategy to tackle climate change, the researchers argued. “Aerosol emissions have major health ramifications,” Gettelman said in a statement. “Saying we should pollute is not practical.”

Greenhouse gas emissions were down 6.4% in 2020 after rising steadily for decades, studies showed. This has been linked with the coronavirus pandemic, with limited economic and social activities worldwide. The US contributed to most of the global decline, with a nearly 13% drop in its emissions due to the limited use of cars.

Under the Paris Agreement on climate change, signed five years ago, countries need to cut one to two billion metric tons per year this decade to limit global warming from rising below 2ºC – the goal set in the climate deal. Still, since it was signed in 2015, emissions have only gone up, a trend only now interrupted by the pandemic.

The study was published in the journal Geophysical Research Letters.

Ocean warming is a wrecking ball for coral reef systems. This researcher wants to understand it all

Year in and year out, scientist Thomas DeCarlo saw the writing on the wall — the wall of coral reefs, that is — and his findings are sounding the alarm: ocean warming and acidification could spell doom for coral reef ecosystems.

Coral reefs are vital for the health of the oceans. Image credits: Olga Tsai.

Billion-dollar buffers

“Ocean temperatures are now approaching one degree above what they were in industrial times, with a projected increase of two to four degrees, which could have terrible consequences for corals,” DeCarlo says.

DeCarlo has studied the history of monsoon upwelling, wind patterns, and other weather factors affecting coral reef ecosystems in the Red Sea. His research shows that reefs are essential not just to the corals themselves, but to the entire surrounding ecosystems, and human society as well.

If reefs collapse, so too do biodiverse life systems that rely on them to survive — and the damage will continue to cascade. Coral reefs are a nursery to different marine species, they provide fish for humans, and they buffer shores from storms.

That storm-buffer feature is apparently quite significant in dollars. In a US Geological Survey report, coral reef barriers as a force in flood protection protect $1.8 billion worth of coastal infrastructure and economic activity in the US and trust territories alone. Reefs reduce the energy of the waves as they wash ashore, which prevents or limits coastal erosion, flooding, and water surges.

DeCarlo’s detailed explorations use microsope, climate models, coral cores, and computerized tomography (CT) analysis, to study the relationship between climate stressors, bleaching, and calcification. He’s not the first scientist to study the environmental impact of coral reefs but he has taken a special look at instances where the upwelling of nutrient levels can be toxic to corals.

Composite photo shows samples of coral cores alongside CT scans of coral skeletal cores showing annual pairs of light and dark bands of high and low density. Photo: Thomas DeCarlo.

His plan, he says, is to build a global database of the history of coral bleaching events, helping to fill the gaps in our knowledge of coral resilience and vulnerability. But to do that, we first need to understand how the climate is affecting corals.

High, hot, and deadly

Winds blowing across the ocean surface push water away. Water then rises up from beneath the surface to replace the water that was pushed away, a process known as “upwelling,” explains the National Ocean Service (NOS). The water that rises to the surface is typically colder and is rich in nutrients, which “fertilize” surface waters, and have high biological productivity.

For corals, upwelling can be a blessing or a curse. According to DeCarlo knows, nutrient-dense waters can spell good news or bad news. It depends.

“Summer monsoons circulate nutrient-dense waters from the Gulf of Aden to the Red Sea. The symbiotic algae that live in corals thrive on these nutrients. In return, they provide food and energy for the corals to grow,” said DeCarlo. “But warmer waters create more nutrients, which create more algae, which create more oxygen and waste build-up in corals. When high waste conditions combine with high heat, this situation causes bleaching, which could turn deadly.”

According to the NOS, bleaching events might or might not be a dire threat for coral. If stress caused bleaching is not severe, the coral may recover. But if (1) there is prolonged algae loss and (2) continued stress, coral eventually dies.

There’s much work to be done, and DeCarlo has no intentions of stopping anytime soon. From King Abdullah University of Science and Technology (KAUST) and now on to Hawaii, at Hawaii Pacific University, his work offered valuable insight into the life of corals, but there’s much more research to be done, especially in regards to global warming. DeCarlo’s website states that “global warming is driving an increase in the frequency of mass coral bleaching events worldwide.”

Healthy coral reef and marine life in the central Red Sea of Saudi Arabia. Photo: KAUST.

It took the researcher 4 years to finish his PhD studying corals, an accomplishment he says he is “especially proud of,” since it was a first of its kind comprehensive study.

One important takeaway from this research is that coral reef environments are not a cookie-cutter affair. One-sized conclusions and conservation measures cannot address and fix everything. One must recognize the complexities due to what are the oceanographic settings of any individual coral reef.

Disentangling these oceanographic processes will help us predict when and where we may find coral reefs that are relatively resistant to rising temperatures, and this information will be critical to informing local management decisions.”

Global warming is literally dissolving the ocean’s plankton

Ocean acidification is wreaking havoc on the ocean’s tiniest inhabitants, and the entire ocean is likely feeling the effects.

The color scale shows shell thickness. Old plankton had thicker, healthier shells than modern samples. Image from Fox et al / Scientific Reports (2020).

As a geology student, many things can be unusual. You start to think about time in millions of years, which is completely counterintuitive. You start to realize just how intricate (and beautiful) the processes that shape our planet are, and you also start to understand that there are firm physical laws governing how our planet looks like. There’s a reason why mountains on Earth don’t grow forever and why the continents move about the way they do — the laws of physics constrain geology, and they constrain nature.

What does this have to do with plankton, one might ask, and the oceans in general?

Well, many of the ocean’s inhabitants have soft bodies protected by hard shells. Clams, oysters, and sea snails have them, as do multiple other types of mollusks and plankton. These seashells are almost always made of calcium carbonate — which, under most conditions, is fine. The ocean water is well-suited to support calcium carbonate under normal conditions. But here, too, there is a physical rule that allows this.

Seawater is slightly basic (meaning pH > 7). When we increase the amount of carbon dioxide (CO2) we emit, not all of it goes into the atmosphere. Much of it, in fact, is absorbed by the oceans. As oceans absorb CO2, their chemistry starts to change, and they become more acidic.

When there is too much carbon dioxide in the oceans, it makes for acidic waters that don’t support seashells. If current emission trends continue, it might spell disaster for many of the ocean’s inhabitants. Image credits: Elisajans / Wikipedia.

When the acidity reaches a certain threshold, animals can no longer build and maintain seashells, and they can’t survive anymore.

This is already happening, a new study shows.

Plankton old, plankton new

The new study started in a museum.

When it comes to comparing our current environment with that of the past, museums can provide a trove of information. The museum is not just what you see when you visit it — museums have additional storage rooms, where they sometimes keep thousands upon thousands of samples gathered by researchers. In this case, Lyndsey Fox, a researcher from Kingston University in London, analyzed plankton fossils gathered by the 1872–76 expedition of the HMS Challenger.

Studying micro-fossils is never an easy task. Analyzing how thick their shells are and then using a tomography scanner to create 3D models of their shells (which are less than 1 millimeter in diameter) is an even trickier job. But Fox and colleagues succeeded, and built stunning reconstructions of this century-old plankton. They then did the same thing for plankton gathered from a 2011 expedition to the eastern equatorial Pacific Ocean called Tara.

The results were striking.

All modern plankton had much thinner shells — up to 76% thinner. In some cases, the shells were so thin that the team wasn’t even able to image them.

No matter where researchers looked, modern plankton had thinner, more vulnerable shells. Image credits: Fox et al / Scientific Reports (2020).

It’s a shocking result. Researchers were well aware that ocean acidification was taking a toll, but the extent to which this was observed is concerning.

Stress on all sides

Some species seem to handle it better than others, presumably due to biological differences among species (though researchers did not attempt to explain this).

“Whilst all specimens analyzed showed some reduction in shell thickness, the degree to which different species responded varied greatly,” the authors of the study write.

There are plenty of old samples in museums, and researchers want to look at more species from different areas of the ocean and study the differences and peculiarities — but the elephant in the room is clear. As we pump more and more carbon dioxide, much of it will end up in our oceans, with long-lasting consequences for the entire ecosystem. We are reaching a point where some organisms are already struggling to maintain their shells, the study highlights.

“Oceanic carbonate ion concentrations decrease as a consequence of increased atmospheric CO2 levels, which, in turn, has a negative effect on the capacity for calcifying organisms (such as molluscs, crustaceans, corals, and foraminifera) to form their essential skeletal or shell material out of calcium carbonate,” the study continues.

It’s not just microscopic creatures, either. A recent study found that ocean acidification is also destroying the shells of crabs, and while some creatures might take it better than others, no creature is spared from its effects. When the plankton suffers, the entire food chain on Earth suffers.

The evil twin of global warming, as ocean acidification is often referred to, is even more insidious than its sibling. We don’t see when plankton is being dissolved in the ocean. We hardly know how many creatures are unable to maintain their shells due to it. We may not know the full scale of the problem, but we know the cause, and we know that if we want to address it, reducing our emissions is key.

To make matters even worse, ocean acidification doesn’t act in a vacuum. The oceans are getting warmer, and as the oceans gather more carbon, they have less available oxygen — which creatures also need. This is a one-two punch which, many creatures are struggling to withstand.

“Ocean acidification is not the only stressor faced by the world’s oceans in the coming decades and over the time period studied here. Rising temperatures and deoxygenation are also likely to have a substantial impact on marine ecosystems, and eastern boundary upwelling systems are likely to be strongly affected by all three stressors,” the study concludes.

We might not see it, but it just goes to show how insidious the effects of global warming really are.

The study was published in Scientific Reports.