Climate Change ☀️
E.P.A. to Sharply Limit Powerful Greenhouse Gases
The Biden administration is moving quickly to limit hydrofluorocarbons, the Earth-warming chemicals used in air-conditioning and refrigeration.

The Environmental Protection Agency moved on Monday to sharply reduce the use and production of powerful greenhouse gases central to refrigeration and air-conditioning, part of the Biden administration’s larger strategy of trying to slow the pace of global warming.

The agency proposed to regulate hydrofluorocarbons, or HFCs, a class of man-made chemicals that are thousands of times more potent than carbon dioxide at warming the planet. The proposal is the first significant step the E.P.A. has taken under President Biden to curb climate change.

The move is also the first time the federal government has set national limits on HFCs, which were used to replace ozone-depleting chlorofluorocarbons in the 1980s but have turned out to be a significant driver of global warming. More than a dozen states have either banned HFCs or are formulating some restrictions.


And it is another sign, along with Mr. Biden’s decision to rejoin the Paris climate accord and to host a recent virtual climate summit — that the administration is reinserting the country into the international fight against global warming.

“This is incredibly significant,” said Kristen N. Taddonio, a senior climate and energy adviser for the Institute for Governance & Sustainable Development, an environmental nonprofit group.

“By taking fast action on these short-lived climate pollutants, of which HFCs are the most potent, we can buy ourselves some time and actually help avoid climate tipping points,” she said.

The regulation would begin to take effect in 2022 and would gradually reduce the production and importation of hydrofluorocarbons in the United States by 85 percent over the following 15 years. About 15 percent of HFCs would still be permitted because they have critical uses for which alternatives do not yet exist.

The E.P.A. estimated that by 2050 the rule would eliminate the equivalent of 4.7 billion metric tons of carbon dioxide, or about three years’ worth of emissions from America’s power sector. That would help put the United States on a path toward meeting Mr. Biden’s aggressive goal of cutting America’s emissions roughly in half by 2035.
Read the full article: https://www.nytimes.com/2021/05/03/climate/EPA-HFCs-hydrofluorocarbons.html

Reduction in wetland areas will affect Afrotropical migratory waterbirds
Study points to need for an integrated approach to fighting impacts of climate change

Migratory waterbirds are particularly exposed to the effects of climate change at their breeding areas in the High Arctic and in Africa, according to a new study. The research team came to this conclusion after modelling climatic and hydrological conditions under current and future climate scenarios (in 2050) and comparing the impact on the distribution of 197 of the 255 waterbird species listed under the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA).
Read the full article: https://www.sciencedaily.com/releases/2021/05/210503093522.htm

Less precipitation means less plant diversity
Climate change might lead to changes in plant diversity, especially in the world's drylands

Water is a scarce resource in many of the Earth's ecosystems. This scarcity is likely to increase in the course of climate change. This, in turn, might lead to a considerable decline in plant diversity. Using experimental data from all over the world, a team of scientists have demonstrated for the first time that plant biodiversity in drylands is particularly sensitive to changes in precipitation.
Read the full article: https://www.sciencedaily.com/releases/2021/05/210503104810.htm

Equipping crop plants for climate change
Biologists have significantly enhanced the tolerance of blue-green algae to high light levels -- with the aid of artificial evolution in the laboratory.

Sunlight, air and water are all that cyanobacteria (more commonly known as blue-green algae), true algae and plants need for the production of organic (i.e. carbon-based) compounds and molecular oxygen by means of photosynthesis. Photosynthesis is the major source of building blocks for organisms on Earth. However, too much sunlight reduces the efficiency of photosynthesis because it damages the 'solar panels', i.e. the photosynthetic machineries of cyanobacteria, algae and plants. A team of researchers led by LMU biologist Dario Leister has now used "artificial laboratory evolution" to identify mutations that enable unicellular cyanobacteria to tolerate high levels of light. The long-term aim of the project is to find ways of endowing crop plants with the ability to cope with the effects of climate change.

The cyanobacteria used in the study were derived from a strain of cells that were used to grow at low levels of light. "To enable them to emerge from the shadows, so to speak, we exposed these cells to successively higher light intensities," says Leister. In an evolutionary process based on mutation and selection, the cells adapted to the progressive alteration in lighting conditions -- and because each cell divides every few hours, the adaptation process proceeded at a far higher rate than would have been possible with green plants. To help the process along, the researchers increased the natural mutation rate by treating cells with mutagenic chemicals and irradiating them with UV light. By the end of the experiment, the surviving blue-green algae were capable of tolerating light intensities that were higher than the maximal levels that can occur on Earth under natural conditions.
Read the full article: https://www.sciencedaily.com/releases/2021/05/210503135618.htm

Human behavior must be factored into climate change analyses
A new Cornell University-led study examines how temperature affects fishing behavior and catches among inland fisher households in Cambodia, with important implications for understanding climate change.

The research, which used household surveys, temperature data and statistical models, revealed that when temperatures rise, people fish less often. At the same time, the study's authors indirectly found that stocks of fish and other aquatic foods also rise with temperatures, leading to slightly larger catches each time peopled fished. Without careful analysis, it would appear that overall fish catches appear unchanged annually, when in fact, more nuanced dynamics are at play.

The study highlights why it's necessary when studying changing environmental conditions to include human behavior along with ecosystem responses; both are key variables when considering how climate change affects rural livelihoods, food production and food access.
Read the full article: https://www.sciencedaily.com/releases/2021/05/210503135638.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