Climate Change ☀️
Reducing global warming matters for freshwater fish species
The habitats of freshwater fish species are threatened by global warming, mainly due to rising water temperatures. A 3.2-degree Celsius increase in global mean temperature would threaten more than half of the habitat for one third of all freshwater fish species. The number of species at risk is ten times smaller if warming is limited to 1.5 degrees.

Many studies have already assessed the potential impacts of climate change on animal and plant species in terrestrial systems. "However, freshwater fish species have been largely ignored, even though they represent approximately a quarter of the global known vertebrate diversity," says Valerio Barbarossa, lead author of the paper. This is the first study that investigated the potential impact of climate change on approximately 11,500 freshwater fish species around the globe.

With a global rise of 3.2 degrees Celsius, a scenario expected if there are no further emission cuts after current governments' pledges for 2030, over one third of the freshwater species have more than half of their present-day habitats threatened by extremes in water temperature or streamflow.

If global warming is limited to 2 degrees, 9% of the species would have more than a half of their habitat threatened. If warming is limited to 1.5 degrees, the number of species at risk reduces to 4%. "These numbers indicate that limiting global warming really matters for freshwater fish species, just as previous research has shown that it matters for species in terrestrial systems," says Barbarossa.
Read the full article: https://www.sciencedaily.com/releases/2021/03/210315110154.htm

Antarctic peninsula likely to warm over next two decades
An analysis of historic and projected simulations from 19 global climate models shows that, because of climate change, the temperature in the Antarctic peninsula -- long a canary in the coal mine for the rest of the continent -- will increase by 0.5 to 1.5 degrees Celsius by 2044.

The projections also showed that precipitation -- a threat to ice if it manifests as rain -- will likely increase on the peninsula by about 5% to 10% over that same time period.

... Since the 1950s, the peninsula, along with the rest of the western part of Antarctica, has been one of the fastest-warming regions on Earth. And because it is covered in mountains -- the highest peak is just over 10,600 feet -- standard climate models overlook some of the nuances of how climate change affects the peninsula, Bromwich said.

"The issue for the Antarctic peninsula is that it's this narrow but high mountain range, and these big models spanning the whole continent don't take that into account.
Our goal was to provide more detail in those projections," he said.

The analysis found that the greatest increases in temperature -- about 2 degrees Celsius -- were likely to happen in the Antarctic fall and winter, but warmer temperatures projected for summer would cause the most trouble.

That could create a double threat to the ice on the peninsula, Bromwich said: Warmer temperatures also mean that some precipitation that might have previously fallen as snow will likely fall as rain.

More rain means less snow on top of the ice, which protects ice from the sun's rays by reflecting them back into the sky.
Read the full article: https://www.sciencedaily.com/releases/2021/03/210315110229.htm

Global river flow contingent upon climate change
Study shows that as climate change impacts extreme flows, it could be worsening river flooding or increasing water scarcity during dry seasons.

More often than ever before, water available in rivers is at the mercy of climate change, international researchers collaborating on a worldwide study with Michigan State University have revealed. The finding could profoundly affect future water and food security around the world.

"Previous research has shown that river flows have been changing over time globally but the causes were not known. This study shows that the change in stream flow annually or during droughts was primarily caused by climate change during the past 30 years," Pokhrel said.

"This suggests that we are on course to lose more and more water in rivers as climate change continues, which could seriously undermine our ability to maintain water supplies for drinking, industries, power generation, and food production."
Read the full article: https://www.sciencedaily.com/releases/2021/03/210315115027.htm

Important forests and wetlands are disappearing in Belize
Using NASA satellite images and machine learning, researchers have mapped changes in the landscape of northwestern Belize over a span of four decades, finding significant losses of forest and wetlands, but also successful regrowth of forest in established conservation zones that protect surviving structures of the ancient Maya.

The research serves as a case study for other rapidly developing and tropical regions of the globe, especially in places struggling to balance forest and wetland conservation with agricultural needs and food security.

"Broad-scale global studies show that tropical deforestation and wetland destruction is occurring rapidly, which contributes to climate change in multiple ways such as through greenhouses gas increases," said Timothy Beach, the study's co-author and professor in the Department of Geography and the Environment at UT Austin. "These also lead to more runoff and water pollution in much of the Global South. Belize has served as our long-term environmental research laboratory for this global dilemma."
Read the full article: https://www.sciencedaily.com/releases/2021/03/210315132125.htm

European summer droughts since 2015 unprecedented in past two millennia
Recent summer droughts in Europe are far more severe than anything in the past 2,100 years, according to a new study.

An international team, led by the University of Cambridge, studied the chemical fingerprints in European oak trees to reconstruct summer climate over 2,110 years. They found that after a long-term drying trend, drought conditions since 2015 suddenly intensified, beyond anything in the past two thousand years.

This anomaly is likely the result of human-caused climate change and associated shifts in the jet stream. The results are reported in the journal Nature Geoscience.

Recent summer droughts and heatwaves in Europe have had devastating ecological and economic consequences, which will worsen as the global climate continues to warm.
Read the full article: https://www.sciencedaily.com/releases/2021/03/210315132141.htm

The Greenland ice sheet may be more vulnerable than we knew to global warming, new study shows
The findings, published Monday in the Proceedings of the National Academy of Sciences, indicate that the biggest reservoir of ice in the Northern Hemisphere can collapse due to relatively small increases in temperature over a long period of time. That makes it even more vulnerable to human-caused warming, which is causing the Earth to warm faster now than at any other period in its history.

“We know the Greenland ice sheet has this threshold,” Christ said — and humanity is pushing it.

Greenhouse gas emissions from human activities have already raised global average temperatures more than 1 degree Celsius (1.4 degrees Fahrenheit) since 1880. Greenland is losing ice at its fastest rate since humans invented agriculture, causing about 14 millimeters of sea level rise in the past half century.

If the island’s entire ice sheet were to melt now, global sea levels would rise by more than 20 feet.
Read the full article: https://www.washingtonpost.com/climate-environment/2021/03/15/greenland-ice-sheet-more-vulnerable/

New EPA administrator: ‘Science is back’
In his first interview as the nation’s top environmental official, Michael Regan says he is focused on restoring morale at the agency, combatting climate change and lifting up communities burdened by pollution

Michael Regan has bold aspirations, and a long to-do list, as President Biden’s newly confirmed Environmental Protection Agency administrator.

He wants to hasten the nation’s shift to cleaner forms of energy, make transformational investments in communities battered by decades of pollution, and improve air and water quality around the country. But to accomplish any of that, the 44-year-old administrator said Monday, he must first help the EPA get its groove back.


“We’ve got a lot of work to do, starting with rebuilding the staff morale and getting all of our staff back to feeling as if they matter, their voices matter,” Regan said in his first interview after being sworn in last week. “We really have to restore the scientific integrity and the utilization of data, of facts, as we move forward and make some very important decisions.”

Just days into his tenure, the former North Carolina environmental official has embraced a simple mantra as he faces the daunting task of translating Biden’s promises into actual policies.

“Science is back at EPA,” he said.
Read the full article: https://www.washingtonpost.com/climate-environment/2021/03/15/michael-regan-epa-administrator/

Study predicts the oceans will start emitting ozone-depleting CFCs
The ocean, a longtime reservoir for CFC-11, will become a source of the ozone-depleting chemical by middle of next century.

The world's oceans are a vast repository for gases including ozone-depleting chlorofluorocarbons, or CFCs. They absorb these gases from the atmosphere and draw them down to the deep, where they can remain sequestered for centuries and more.

Marine CFCs have long been used as tracers to study ocean currents, but their impact on atmospheric concentrations was assumed to be negligible. Now, MIT researchers have found the oceanic fluxes of at least one type of CFC, known as CFC-11, do in fact affect atmospheric concentrations. In a study appearing today in the Proceedings of the National Academy of Sciences, the team reports that the global ocean will reverse its longtime role as a sink for the potent ozone-depleting chemical.

The researchers project that by the year 2075, the oceans will emit more CFC-11 back into the atmosphere than they absorb, emitting detectable amounts of the chemical by 2130. Further, with increasing climate change, this shift will occur 10 years earlier. The emissions of CFC-11 from the ocean will effectively extend the chemical's average residence time, causing it to linger five years longer in the atmosphere than it otherwise would. This may impact future estimations of CFC-11 emissions.

The new results may help scientists and policymakers better pinpoint future sources of the chemical, which is now banned worldwide under the Montreal Protocol.
Read the full article: https://www.sciencedaily.com/releases/2021/03/210315160722.htm

Scientists stunned to discover plants beneath mile-deep Greenland ice
Long-lost ice core provides direct evidence that giant ice sheet melted off within the last million years and is highly vulnerable to a warming climate Scientists found frozen plant fossils, preserved under a mile of ice on Greenland. The discovery helps confirm a new and troubling understanding that the Greenland Ice Sheet has melted entirely during recent warm periods in Earth's history -- like the one we are now creating with human-caused climate change. The new study provides strong evidence that Greenland is more sensitive to climate change than previously understood -- and at risk of irreversibly melting.
Read the full article: https://www.sciencedaily.com/releases/2021/03/210315165639.htm

Climate change, periodic modification of Earth’s climate brought about as a result of changes in the atmosphere as well as interactions between the atmosphere and various other geologic, chemical, biological, and geographic factors within the Earth system.

Source: Climate change - Evidence for climate change | Britannica
Climate Change is the defining issue of our time and we are at a defining moment. From shifting weather patterns that threaten food production, to rising sea levels that increase the risk of catastrophic flooding, the impacts of climate change are global in scope and unprecedented in scale. Without drastic action today, adapting to these impacts in the future will be more difficult and costly.

Source: Climate Change | United Nations