Climate Change ☀️
Northern Red Sea corals pass heat stress test with flying colors
Scientists are beginning to understand why corals in the Gulf of Aqaba, along with their symbiotic algae and bacteria, resist higher temperatures particularly well.

Even under the most optimistic scenarios, most of the coral reef ecosystems on our planet -- whether in Australia, the Maldives or the Caribbean -- will have disappeared or be in very bad shape by the end of this century. That's because global warming is pushing ocean temperatures above the limit that single-cell algae, which are corals' main allies, can withstand. These algae live inside coral tissue for protection and, in exchange, provide corals with essential nutrients produced through photosynthesis. Because the algae contain a variety of pigments and therefore give coral reefs their famous colors, if they are lost the corals turn white, which is known as coral bleaching. But in spite of the real threat caused by global warming, corals in the Red Sea look set to keep their vibrant color.
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Catastrophic sea-level rise from Antarctic melting possible with severe global warming
Antarctic ice sheet is more likely to remain stable if Paris climate agreement is met

The Antarctic ice sheet is much less likely to become unstable and cause dramatic sea-level rise in upcoming centuries if the world follows policies that keep global warming below a key 2015 Paris climate agreement target, according to a Rutgers coauthored study.

But if global warming exceeds the target -- 2 degrees Celsius (3.6 degrees Fahrenheit) -- the risk of ice shelves around the ice sheet's perimeter melting would increase significantly, and their collapse would trigger rapid Antarctic melting. That would result in at least 0.07 inches of global average sea-level rise a year in 2060 and beyond, according to the study in the journal Nature.

That's faster than the average rate of sea-level rise over the past 120 years and, in vulnerable coastal places like downtown Annapolis, Maryland, has led to a dramatic increase in days of extreme flooding.
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Antarctica remains the wild card for sea-level rise estimates through 2100
A massive collaborative research project covered in the journal Nature this week offers projections to the year 2100 of future sea-level rise from all sources of land ice, offering the most complete projections created to date.

The estimates show that limiting global warming to 1.5 degrees C above pre-industrial temperatures would cut projected 21st century sea-level rise from land ice in half, relative to currently pledged emissions reductions. For example, the paper notes that, when looking at all land ice sources, the median projection of cumulative rise in sea level by the year 2100 decreases from approximately 25 cm to approximately 13 cm when emissions are limited.

The term "land ice" includes mountain glaciers such as those in Alaska, Europe, high-mountain Asia, etc.; ice caps including those of Iceland and the Canadian Arctic; and ice sheets in Greenland and Antarctica.
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Flooding might triple in the mountains of Asia due to global warming
A research team has revealed the dramatic increase in flood risk that could occur across Earth's icy Third Pole in response to ongoing climate change. Focusing on the threat from new lakes forming in front of rapidly retreating glaciers, a team demonstrated that the related flood risk to communities and their infrastructure could almost triple. Important new hotspots of risk will emerge, including within politically sensitive transboundary regions of the Himalaya and Pamir.

The "Third Pole" of the Earth, the high mountain ranges of Asia, bears the largest number of glaciers outside the polar regions. A Sino-Swiss research team has revealed the dramatic increase in flood risk that could occur across Earth's icy Third Pole in response to ongoing climate change. Focusing on the threat from new lakes forming in front of rapidly retreating glaciers, a team, led by researchers from the University of Geneva (UNIGE), Switzerland, demonstrated that the related flood risk to communities and their infrastructure could almost triple. Important new hotspots of risk will emerge, including within politically sensitive transboundary regions of the Himalaya and Pamir. With significant increases in risk already anticipated over the next three decades, the results of the study, published in Nature Climate Change, underline the urgent need for forward-looking, collaborative, long-term approaches to mitigate future impacts in the region.

The Hindu Kush-Himalaya, Tibetan Plateau and surrounding mountain ranges are widely known as the Third Pole of the Earth. Due to global warming, the widespread and accelerated melting of glaciers over most of the region has been associated with the rapid expansion and formation of new glacial lakes. When water is suddenly released from these lakes through failure or overtopping of the dam, glacial lake outburst floods can devastate lives and livelihoods up to hundreds of kilometres downstream, extending across international borders to create transboundary risks. Despite the severe threat that these extreme events pose for sustainable mountain development across the Third Pole, there has been a lack of understanding regarding where and when related risks would evolve in the future.
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Hydrogen instead of electrification? Potentials and risks for climate targets
Hydrogen-based fuels should primarily be used in sectors such as aviation or industrial processes that cannot be electrified, finds a team of researchers. Producing these fuels is too inefficient, costly and their availability too uncertain, to broadly replace fossil fuels for instance in cars or heating houses. For most sectors, directly using electricity for instance in battery electric cars or heat pumps makes more economic sense. Universally relying on hydrogen-based fuels instead and keeping combustion technologies threatens to lock in a further fossil fuel dependency and greenhouse gas emissions.

"Hydrogen-based fuels can be a great clean energy carrier -- yet great are also their costs and associated risks," says lead author Falko Ueckerdt from the Potsdam Institute for Climate Impact Research (PIK). "Fuels based on hydrogen as a universal climate solution might be a bit of false promise. While they're wonderfully versatile, it should not be expected that they broadly replace fossil fuels. Hydrogen-based fuels will likely be scarce and not competitive for at least another decade. Betting on their wide-ranging use would likely increase fossil fuel dependency: if we cling to combustion technologies and hope to feed them with hydrogen-based fuels, and these turn out to be too costly and scarce, then we will end up further burning oil and gas and emit greenhouse gases. This could endanger short- and long-term climate targets."
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The world needs to dramatically cut methane emissions to avoid worst of climate change, UN says
A landmark United Nations report has declared that drastically cutting emissions of methane, a key component of natural gas, is necessary to avoid the worst impacts of global climate change.

The report, published Thursday by the Climate and Clear Coalition and the U.N. Environment Programme, represents a shift in the worldwide conversation on how to best address the climate crisis, which has focused on longer-term carbon dioxide reduction.

Methane is 84 times more potent than carbon and doesn't last as long in the atmosphere before it breaks down. This makes it a critical target for reducing global warming more quickly while simultaneously working to reduce other greenhouse gases.

More than half of global methane emissions come from oil and gas extraction in the fossil fuel industry, landfills and wastewater from the waste sector, and livestock emissions from manure and enteric fermentation in the agricultural sector.

The world could slash methane emissions by up to 45% this decade, or 180 million tons a year, according to the U.N.'s Global Methane Assessment. Such a target will avoid nearly 0.3 degrees Celsius of warming by 2045 and help limit the rise in global temperatures to 1.5 degrees Celsius, a goal of the Paris climate accord.
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China's greenhouse gas emissions exceed those of U.S. and developed countries combined, report says
China's greenhouse gas emissions in 2019 exceeded those of the U.S. and the developed world combined, according to a report published Thursday by research and consulting firm Rhodium Group.

The country's emissions more than tripled during the past three decades, the report added.

China is now responsible for more than 27% of total global emissions. The U.S., which is the world's second-highest emitter, accounts for 11% of the global total. India is responsible for 6.6% of global emissions, edging out the 27 nations in the EU, which account for 6.4%, the report said.
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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