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

Scientists complete largest global assessment of ocean warming impacts

A group of international marine scientists has compiled the most comprehensive assessment of how ocean warming is affecting the mix of species in our oceans – and explained how some marine species manage to keep their cool.

Martin Edwards from the University of Plymouth along with other researchers from the UK, Japan, Australia, USA, Germany, Canada, South Africa and New Zealand analysed three million records of thousands of species from 200 ecological communities across the globe.

Reviewing data from 1985 – 2014, the team led by Michael Burrows of the Scottish Association for Marine Science (SAMS) in Oban showed how subtle changes in the movement of species that prefer cold-water or warm-water, in response to rising temperatures, made a big impact on the global picture. The findings, published in the journal Nature Climate Change [https://www.nature.com/articles/s41558-019-0631-5], show how warm-water species increase and cold-water marine species become less successful as the global temperature rises. However, the study also suggests that some cold-water species, and fish in particular, will continue to thrive by seeking refuge in cooler, deeper water.

Prof Burrows  further added:

“For the period from 1985 – 2014 we created the equivalent of an electoral poll in the ocean, showing swings between types of fish and plankton normally associated with either cold or warm habitats. As species increase in number and move into, or decline and leave, a particular ecological community, the make-up of that community will change in a predictable way. While this may not sound like a big change, it has a considerable impact on species that may already be on, or close to, their maximum temperature tolerance. A gradual temperature change like the one we are witnessing is not going to cause extinctions overnight but it is affecting the success of many species, not least zooplankton such as copepods, which are crucial to the ocean food web”.

Prof Edwards said the truly global study looked at data from the North Atlantic, Western Europe, Newfoundland and the Labrador Sea, east coast USA, the Gulf of Mexico, and the North Pacific from California to Alaska. While the global warming trend was widely seen, the North Atlantic showed the largest rise in average temperature during the time period. This area of the North Atlantic is routinely monitored by one of the world’s largest and longest marine biological surveys known as the Continuous Plankton Recorder (CPR) Survey which provided some key observational data in the global study. The changes observed have been driven by a seemingly small but ecologically significant rise in temperature of almost one degree Celsius in some parts of the ocean since 1985, a rapid change in just three decades. These changes are having huge implications for the abundance and distribution of plankton in our oceans.



Climate-related changes in fish and plankton communities shown by changes in Community Temperature Index values from 1985 to 2015.

Plymouth scientists highlight effects of climate change on UK’s plankton

Marine scientists in Plymouth have led a major study highlighting the effects of climate change on the plankton populations in UK seas.

Published as part of a wide-ranging report by the Marine Climate Change Impacts Partnership (MCCIP), it shows there have been extensive changes in plankton ecosystems around the British Isles over the last 60 years.

It says climate variability and ocean warming have had negative impacts on plankton production, biodiversity and species distributions, which have in turn affected fisheries production and other marine life such as seabirds.

The study was written by world-leading researchers from the University of Plymouth and Plymouth Marine Laboratory, along with colleagues at Marine Scotland Science and the Centre for Environment Fisheries and Aquaculture Science.

It forms part of the MCCIP Report Card 2020, which summarises 26 individual, peer-reviewed scientific reports to provide detailed evidence of observed and projected climate change impacts and identify emerging issues and knowledge gaps.

Emergence of a cold-water ‘blob’ in the North Atlantic sub-polar gyre region

Martin Edwards, Professor of Ocean Ecology at the University of Plymouth, led the report on plankton. He said:

“There have been extensive changes in plankton ecosystems around the British Isles over the last 60 years, mainly driven by climate variability and ocean warming. For example, during the last 50 years there has been a northerly movement of some warmer water plankton by 10° latitude in the North-east Atlantic and a similar retreat of colder water plankton. Future warming is likely to alter the geographical distribution of plankton abundance and these changes may place additional stress on already depleted fish stocks, as well as having consequences for mammal and seabird populations.”

Among the key factors highlighted in the plankton report are:

  • There has been a shift in the distribution of many plankton and fish species around the planet.
  • The North Sea populations of previously dominant and important zooplankton species (the cold water species Calanus finmarchicus, a major food source for fish, shrimp and whales) have declined in biomass by 70% since the 1960s.
  • Species with warmer-water affinities (e.g. Calanus helgolandicus) are moving northwards to replace the species, but are not as numerically abundant.
  • The decline of the European cod stocks due to overfishing may have been exacerbated by climate warming and climate-induced changes in plankton production.
  • Future warming is likely to alter the geographical distribution of primary and secondary open ocean (pelagic) production, affecting ecosystem services such as oxygen production and the removal of carbon dioxide from the atmosphere.

Get the report here: