Tag Archives: West

Iceberg.

Arctic ecosystems “highly responsive” to climate change — and very hard to fix once broken

Climate change is impacting the Arctic far quicker than we’ve assumed, an international team of researchers reports. Other research looking into how Arctic life fared after the meteorite impact that wiped out the dinosaurs gives us a glimpse into how ecosystems in the area might evolve under climate change.

Iceberg.

Image credits Rolf Johansson.

Ecosystems in the Arctic undergo rapid, dramatic, and long-lasting changes in response to climate shifts — even those of average magnitude, according to a new study published in Environmental Research Letters. The study, conducted by an international research team led by members from the University of Maine, finds a “surprisingly tight coupling” between climate shifts and environmental responses in the Arctic. The paper thus overturns previous assumptions that environmental responses are delayed or dampened by internal ecosystem dynamics, allowing only significant climate shifts to have an effect on local ecosystems.

The heat is on

“Our analyses reveal rapid environmental responses to nonlinear climate shifts, underscoring the highly responsive nature of Arctic ecosystems to abrupt transitions,” the study’s abstract reads.

After 1994, mean air temperatures over West Greenland (as recorded in June) were 2.2°C higher than baseline, the team reports, and have increased by an additional 1.1°C since 2006. Mean winter precipitation also doubled in quantity (from 20mm to 40mm) over the area after 1994.

The findings come from over 40 years’ worth of weather data and paleoecological reconstructions. The team explains that these “abrupt climate shifts” were accompanied by “nearly synchronous” environmental responses in the area, including increased ice sheet discharge and dust, and advanced plant phenology (i.e. earlier onset of the life cycles of plants in the area). Lakes in the area experienced earlier ice-outs and greater diversity of algae.

In light of these findings, the team cautions that Arctic ecosystems are much more responsive to abrupt transitions — even moderate magnitude ones — than assumed. The strength of climate forcing (i.e. warming) in the area has also been underestimated, they add. Understanding how these ecosystems respond to abrupt climate change is key to predicting their evolution in the future and managing potentially damaging shifts says Jasmine Saros, the paper’s lead author.

“We present evidence that climate shifts of even moderate magnitude can rapidly force strong, pervasive environmental changes across a high-latitude system,” she says.

“Prior research on ecological response to abrupt climate change suggested delayed or dampened ecosystem responses. In the Arctic, however, we found that nonlinear environmental responses occurred with or shortly after documented climate shifts in 1994 and 2006.”

How does this pan out?

Penguins.

Penguins don’t live in the Arctic but they’re cute, so here’s a picture of some.
Image credits Siggy Nowak.

Another unrelated study published in the journal Palaeontology looked at how life on the other end of the planet — Antarctica — recovered after the impact of Chicxulub, the dinosaur-killing meteorite. This impact triggered a massive, planet-wide extinction event known as the Cretaceous-Paleogene (K-Pg) mass extinction some 66 million years ago.

Although the effects of this impact (e.g. transient cooling, global darkness, and expansion of anoxic waters) were “probably short-lived, […] biogeochemical cycling and ecosystem function remained disturbed for an extended period”. It took local marine ecosystems roughly one million years to return to pre-extinction levels, they explain.

The K-Pg event was caused by the impact of a 10 km asteroid on the Yucatán Peninsula, Mexico, and took place while our planet was already in the throes of environmental instability caused by a major volcanic episode. In the end, Chicxulub’s visit would wipe out around 60% of the marine species around Antarctica, and 75% of species around the world. This turned out to be quite a fortunate development for us humans, as the impact fundamentally changed the evolutionary history of life on Earth. Most of the animal groups you know today, including us mammals, were only able to rise as a direct consequence of this impact.

“This study gives us further evidence of how rapid environmental change can affect the evolution of life,” says Dr. Rowan Whittle, a palaeontologist at British Antarctic Survey and the study’s lead author.

“Our results show a clear link in the timing of animal recovery and the recovery of Earth systems.”

For over 320,000 years after the extinction, the team reports, the Antarctic sea floor was dominated by burrowing clams and snails. It took roughly one million years for the number of species to recover to pre-extinction levels.

“Our discovery shows the effects of the K-Pg extinction were truly global, and that even Antarctic ecosystems, where animals were adapted to environmental changes at high latitudes like seasonal changes in light and food supply, were affected for hundreds of thousands of years after the extinction event.”

Now, needless to say, the K-Pg extinction event was way more abrupt and dramatic than the shifts we’re causing in the Earth’s climate today. And this study focuses on its effects in Antarctica, not the Arctic. However, it does serve as an adequate case-study to see how long such ecosystems need to recover from major environmental shocks.

And climate change (plus human activity) is a major environmental shock. It’s much slower than an asteroid impact, sure, but it’s still happening unbelievably fast from a geological and evolutionary point of view. The first study we’ve discussed here shows that Arctic ecosystems do feel the heat, and feel it fast. Life here is very specialized to thrive in its frigid niche and if we let these ecosystems collapse, the same ancient dynamics that Whittle’s team found in the Antarctic will likely apply — our Arctic will only recover as the Earth’s systems recover.

The paper “Arctic climate shifts drive rapid ecosystem responses across the West Greenland landscape” has been published in the journal Environmental Research Letters.

The paper “Nature and timing of biotic recovery in Antarctic benthic marine ecosystems following the Cretaceous–Palaeogene mass extinction” has been published in the journal Palaeontology.

Iceberg.

Nearly one quarter of West Antarctica ice is unstable, melting, study reports

Over the last 25 years, Antarctica’s ice sheet has thinned by up to 122 meters in certain areas. The most heavily-hit area is West Antarctica, where ocean melting is speeding up the process. However, affected glaciers are becoming unstable throughout the frozen continent, a new paper reports, meaning they lose more ice through melting and calving than they gain from snowfall.

Iceberg.

Image via Pixabay.

The authors of the study, a team from the UK Centre for Polar Observation and Modelling (CPOM) led by Professor Andy Shepherd from the University of Leeds, used 25 years’ worth of altimetry data recorded by European Space Agency satellites and a regional climate model to determine the state of Antarctic ice.

Antarctic, shaken, no ice, please

“In parts of Antarctica the ice sheet has thinned by extraordinary amounts, and so we set out to show how much was due to changes in climate and how much was due to weather,” Professor Shepherd explains.

“While the majority of the ice sheet has remained stable, 24% of West Antarctica is now in a state of dynamical imbalance,” the paper reads.

The patterns of glacier thinning have not been static, the team reports. Since 1992, glaciers across more than 24% of West Antarctica has begun to thin, as did those associated with the continent’s largest ice streams — the Pine Island and Thwaites Glaciers. These two glaciers are now melting a full five times faster than they were at the beginning of the survey, the team notes. All in all, fluctuations in snowfall do cause small changes in glacier volume for a few years at a time, but the significant changes observed by the team have persisted for decades and are indicative of the effects of climate-change-induced glacier instability, the team explains.

The data used in the study included over 800 million measurements of the Antarctic ice sheet height recorded by the ERS-1, ERS-2, Envisat, and CryoSat-2 satellite altimeter missions between 1992 and 2017 and simulations of snowfall over the same period produced by the RACMO regional climate model. This wealth of data allowed the team to tease apart changes in ice sheet height caused by weather — such as variations in snowfall — from longer-term changes caused by climate — such as warmer ocean water that melts ice away. To separate the two effects, the researchers compared the surface height readings obtained in the field to changes in snowfall they simulated using the RACMO model. In effect, any discrepancies between the two datasets are the product of glacier imbalance (i.e. of climate change).

“Knowing how much snow has fallen has really helped us to detect the underlying change in glacier ice within the satellite record,” says Professor Shepherd. “We can see clearly now that a wave of thinning has spread rapidly across some of Antarctica’s most vulnerable glaciers, and their losses are driving up sea levels around the planet.”

“Altogether, ice losses from East and West Antarctica have contributed 4.6 mm to global sea level rise since 1992.”

The study is a good example of how satellite data can be used to study large climate trends ongoing on our planet. This is especially true in hostile environments such as the arctic and antarctic, where ground-level missions are not only difficult but potentially deadly, as well.

The paper “Trends in Antarctic Ice Sheet Elevation and Mass” has been published in the journal Geophysical Research Letters.

West Nile.

Indiana’s health officials warn of West Nile virus spotted in mosquitoes in Elkhart, Carroll County

Indiana state officials urge locals in Elkhart and Carroll County to take precautions after mosquitoes in the area tested positive for the West Nile virus.

West Nile.

West Nile Virus.
Image via Cynthia Goldsmith (CDC) / Public Domain.

West Nile virus is a mosquito-borne virus known to be present in Africa, Asia, Europe, and the Middle East — and, since 1999, the Americas as well. It’s quite a nasty bug. The milder form of the illness,  West Nile fever, can include fever, headache, body aches, swollen lymph glands, or a rash. More severe forms of the disease affect the nervous system and include inflammation in the brain and spinal cord (encephalitis), meningitis (inflammation of the tissues that wrap around the brain and spinal cord), muscle paralysis, even death.

It generally likes to infect wild birds. Mosquitoes bite infected birds and transmit the virus over to humans. In the US, it was first identified in wild birds in Indiana in 2001; up to now, it has been found in “most states along the eastern coast and east of the Mississippi River,” according to the Indiana State Department of Health (ISDH).

As of June 27, the ISDH released a warning to locals in Elkhart and Carroll County (link goes to the ISDH’s live monitoring of the virus) that the virus has been detected in mosquitoes in the area. State Health Commissioner Kris Box adds that there is no need to panic. No human cases have been detected as of now, and it’s actually not that uncommon for West Nile to be spotted around these parts — it happens every year. The ISDH expects to continue to see increased West Nile activity throughout the state as the mosquito season progresses.

State officials urge residents to take precautions — especially since the risk of infection is highest during the summer months. Some of the ways you can protect yourself from infection with the virus include:

  • Avoid being outdoors when mosquitoes are active, especially late afternoon, dusk to dawn and early morning.
  • Apply an EPA-registered insect repellent containing DEET, picaridin, IR3535, oil of lemon eucalyptus, or para-menthane-diol to clothes and exposed skin.
  • Cover exposed skin by wearing a hat, long sleeves, and long pants in places where mosquitoes are especially active, such as wooded areas.
  • Install or repair screens on windows and doors to keep mosquitoes out of the home.

Residents should also take the following steps to eliminate potential mosquito breeding grounds:

  • Discard old tires, tin cans, ceramic pots or other containers that can hold water.
  • Repair failing septic systems.
  • Drill holes in the bottom of recycling containers left outdoors.
  • Keep grass cut short and shrubbery trimmed.
  • Clean clogged roof gutters, particularly if leaves tend to plug up the drains.
  • Frequently replace the water in pet bowls.
  • Flush ornamental fountains and birdbaths periodically.
  • Aerate ornamental pools, or stock them with predatory fish.