Will climate change outpace species adaptation?

Species evolve heat tolerance more slowly than cold tolerance

Many species might be left vulnerable in the face of climate change, unable to adapt their physiologies to respond to rapid global warming. According to a team of international researchers, species evolve heat tolerance more slowly than cold tolerance, and the level of heat they can adapt to has limits.

In a study published in the Nature Communications, McGill professor Jennifer Sunday and her co-authors wanted to understand how species’ thermal limits have evolved. To examine variation across the tree of life, the researchers developed the largest available database compiling thermal tolerances for all types of organisms (GlobTherm database).

Migrating mullet

The researchers found that first and foremost, a species’ thermal tolerance is linked to the current climate where they live. “It’s logical that thermal limits mostly match a species’ present-day climate but tracing the evolutionary history of thermal limits can reveal how species got to be where they are today,” says Sunday, an Assistant Professor in the Department of Biology.

The researchers also found that tolerance to cold has evolved much faster than tolerance to heat, particularly in endotherms as compared to ectotherms and plants. Endothermic animals are those that generate metabolic heat to regulate their own body temperature – for example, mammals and birds – while ectothermic animals are those that regulate their body temperature using external heat sources, like reptiles, fishes and invertebrates.

One cause of this disparity could be that heat tolerance has reached an evolutionary barrier, called an ‘attractor,’ beyond which further evolution is constrained or selected against. “This is very concerning because it suggests that the vast majority of species will not be able to adapt fast enough to survive the unprecedented rate of contemporary climate change,” says co-author Joanne Bennett of Leipzig University and University of Canberra.

The results of this study are particularly relevant to conservation management, say the researchers. Protecting and creating areas that provide refuges for biodiversity from upper temperature extremes is a key strategy for conservation managers.

More information: DOI: https://doi.org/10.1038/s41467-021-21263-8

Are cold winters in Europe caused by melting sea-ice in the Arctic?

They are diligently stoking thousands of bonfires on the ground close to their crops, but the French winemakers are fighting a losing battle. An above-average warm spell at the end of March has been followed by days of extreme frost, destroying the vines with losses amounting to 90 percent above average. The image of the struggle may well be the most depressingly beautiful illustration of the complexities and unpredictability of global climate warming. It is also an agricultural disaster from Bordeaux to Champagne.

Nasa

It is the loss of the Arctic sea-ice due to climate warming that has, somewhat paradoxically, been implicated with severe cold and snowy mid-latitude winters.

“Climate change doesn’t always manifest in the most obvious ways. It’s easy to extrapolate models to show that winters are getting warmer and to forecast a virtually snow-free future in Europe, but our most recent study shows that is too simplistic. We should beware of making broad sweeping statements about the impacts of climate change.” Says professor Alun Hubbard from CAGE Center for Arctic Gas Hydrate, Environment and Climate at UiT The Arctic University of Norway.

Melting Arctic sea ice supplied 88% of the fresh snow

Hubbard is the co-author of a study in Nature Geoscience examining this counter-intuitive climatic paradox: A 50% reduction in Arctic sea-ice cover has increased open-water and winter evaporation to fuel more extreme snowfall further south across Europe.

The study, led by Dr. Hanna Bailey at the University of Oulu, Finland, has more specifically found that the long-term decline of Arctic sea-ice since the late 1970s had a direct comparison to one specific weather event: “Beast from the East”—the February snowfall that brought large parts of the European continent to a halt in 2018, causing £1bn a day in losses.

Researchers discovered that atmospheric vapor traveling south from the Arctic carried a unique geochemical fingerprint, revealing that its source was the warm, open-water surface of the Barents Sea, part of the Arctic Ocean between Norway, Russia, and Svalbard. They found that during the “Beast from the East,” open-water conditions in the Barents Sea supplied up to 88% of the corresponding fresh snow that fell over Europe.

Climate warming is lifting the lid off the Arctic Ocean

“What we’re finding is that sea-ice is effectively a lid on the ocean. And with its long-term reduction across the Arctic, we’re seeing increasing amounts of moisture enter the atmosphere during winter, which directly impacts our weather further south, causing extreme heavy snowfalls. It might seem counter-intuitive, but nature is complex and what happens in the Arctic doesn’t stay in the Arctic.” says Bailey.

When analyzing the long-term trends from 1979 onwards, researchers found that for every square meter of winter sea-ice lost from the Barents Sea, there was a corresponding 70 kg increase in the evaporation, moisture, and snow falling over Europe.

“This study illustrates that the abrupt changes being witnessed across the Arctic now, really are affecting the entire planet,” says professor Hubbard.

Their findings indicate that within the next 60 years, a predicted ice-free Barents Sea will likely become a significant source of increased winter precipitation—be it rain or snow—for Europe.

More information: Hannah Bailey et al, Arctic sea-ice loss fuels extreme European snowfall, Nature Geoscience (2021). DOI: 10.1038/s41561-021-00719-y

Provided by UiT The Arctic University of Norway