climate projections

Climate Change And Species Tipping Points | Earth Wise

June 22, 2023 By EarthWise Leave a Comment

In climate science, tipping points are critical thresholds that, once crossed, lead to large and often irreversible changes in the climate system. For example, surpassing a 1.5 degree C rise in global warming has long been considered a tipping point for the planet.

According to a new study led by researchers from University College London, climate change will abruptly push species over tipping points as their geographic ranges reach unforeseen temperatures.

In the study, which was recently published in the journal Nature Ecology and Evolution, the research team analyzed data from more than 35,000 species of animals and seagrasses from every continent and ocean basin, alongside climate projections up to 2100. The researchers found a consistent trend: for many animals, the thermal exposure threshold will be crossed for much of their geographic range within the same decade.

The thermal exposure threshold is defined as the first five consecutive years where temperatures consistently exceed the most extreme monthly temperature experienced by a species across its geographic range over recent history.

The researchers also found that the extent of global warming will make a big difference for animals. If the planet warms by just 1.5°C, 15% of species studied will be at risk of experiencing unfamiliarly hot temperatures across at least 30% of their current geographic range in a single decade. But this figure will double to 30% of species at 2.5°C of warming.

Since their data provides an early warning system, the researchers hope that their findings will help species conservation efforts.

**********

Web Links

Climate change to push species over abrupt tipping points

Photo, posted May 27, 2017, courtesy of Sarah Lemarié via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Crops May Need To Move | Earth Wise

October 5, 2020 By EarthWise Leave a Comment

California has unique micro-climate diversity that creates ideal growing conditions for a wide range of crops. One third of the vegetables and two-thirds of the fruits and nuts we eat in this country are grown on the more than 76,000 farms in California. But as the climate continues to change, many farmers have started to worry about where and when crops can be grown in the future. Within the next 20 years or so, some parts of California may become too hot and dry to sustain agricultural production.

According to new research from the Lawrence Berkeley National Laboratory, by the years 2045-2049, warmer temperatures will have a significant effect on cool-season crops such as broccoli and lettuce such that their growing season will need to shift. On the other hand, warm-season crops like cantaloupe, tomatoes, and carrots will need to move to entirely new growing locations.

The study looked at five key crops that are produced more in California than elsewhere and studied the climate conditions under which they prosper and those under which they fail. They established the range of conditions for which the crops can remain successful. Finally they looked at climate projections for various parts of the state.

California’s agriculture is an essential part of our food security, so it is important to predict how future warming will affect when and where crops can be grown. Changing these things presents challenges. For example, when considering relocating crops, growers have specialized knowledge of their land and their crops. If crops need to move to a new area, either the farmers have to move to that area, or they have to grow a different crop. Either way, it presents a practical and economic burden on the farmer.

**********

Web Links

Some of America’s Favorite Produce Crops May Need to Get a Move On by 2045

Photo, posted June 16, 2011, courtesy of the U.S. Department of Agriculture via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The ‘Biggest Ever’ Arctic Expedition

October 3, 2019 By EarthWise Leave a Comment

The Arctic is warming faster than any other region on Earth. In fact, it’s warming at a rate of almost twice the global average. And, since what happens in the Arctic doesn’t stay in the Arctic, the world is already feeling the effects: rising sea levels, changes in climate and precipitation patterns, increasing severe weather events, and so on.

As a result, researchers from more than a dozen countries have launched the biggest and most complex expedition ever attempted in the Arctic. They plan to freeze Germany’s largest research vessel, the Polarstern, into Arctic sea ice, where it will remain trapped for twelve months. The ship will drift with the sea ice as the sea ice drifts. The vessel will serve as a research laboratory, hosting a rotating crew of 300 scientists. The ice, the ocean, the atmosphere, and even the wildlife will all be sampled. This year-long journey will give researchers their closest look at how the polar climate and its fragile ecosystems are changing.

Led by the Alfred Wegener Institute for Polar and Marine Research in Germany, the Multidisciplinary drifting Observatory for the Study of Arctic Climate project (or MOSAiC) is expected to cost about $150 million.

One major goal of MOSAiC is to improve strikingly uncertain climate projections for the Arctic. Climate models disagree on how much more the Arctic will warm as the concentration of greenhouse gases in the atmosphere rises and sea ice shrinks. Some project a 5ºC rise by 2100 relative to the 1986-2005 average. Others predict a 10ºC increase.

Understanding the complex processes occurring in the Arctic is essential for projecting the future impacts of climate change.

**********

Web Links

Climate scientists prepare for largest ever Arctic expedition

Climate change: Polarstern leaves for ‘biggest ever’ Arctic expedition

Image courtesy of the U.S. Department of Energy Atmospheric Radiation Measurement (ARM) user facility.

Earth Wise is a production of WAMC Northeast Public Radio.