The Himalayas have the largest ice mass in the world outside the poles and experts warn that climate change portends disaster. Just this February northern India was hit by deadly flooding as a glacial dam collapsed. The big picture is clear but events are hard to predict, and meddling with the natural water cycle, for instance by damming rivers, changes the risk profile. In “Preparing for floods on the Third Pole,” published in Science, Tanuj Shukla and Indra Sen make the case for monitoring the mountain range’s glacial lakes from space to gain better understanding of flood risk and save lives by means of an early satellite-based flood warning system. Even in the dry season: Monsoon isn’t the only driver of water surges in the region. In 2013 an avalanche into a glacial lake caused flooding that killed over 5,000 people, also in northern India.
But apropos the monsoon, global heating is expected to make it more intense – and erratic, based on climate models, warns a team of German researchers in Earth System Dynamics. Southeast Asia depends on the monsoon for water: Tardiness or meagerness causes drought – but one can have too much of a good thing. “For every degree Celsius of warming, monsoon rainfalls will likely increase by about 5%,” says lead author Anja Katzenberger from the Potsdam Institute for Climate Impact Research and Ludwig-Maximilian University in Munich. That’s more than had been previously thought, she explains, and adds even more urgency to satellite monitoring of Himalayan glacier lakes. Torrential monsoons aren’t a plus even for agriculture: Even rice crops can get too much water after they sprout.
The oceans are losing oxygen
Meanwhile, the oceans are losing oxygen and have been for decades, Andreas Oschlies of the Helmholtz Center For Ocean Research warns in Nature Communications. How much? A lot: “In the last 50 years, the loss of oxygen accumulates globally to about 2% of the total inventory (regionally sometimes significantly more),” writes Oschlies. Why? Warming of the oceans decreases the solubility of gases, including oxygen, and is causing ocean circulation and vertical mixing to slow. Oschlies warns that the process of oxygen depletion will continue for centuries, even if all CO2 emissions and thus warming at the Earth’s surface were to stop immediately. The depths below 2,000 meters will be worst affected – at the surface, his model shows a faster response to climate action. So, further expansion of the relatively near-surface oxygen minimum zones can be halted within a few years if the emissions were stopped. Which they haven’t been. But an ambitious climate policy can help prevent at least the near-surface ecosystems from suffocating, he urges.
Antarctic might keep some ice
In March 2021, the average concentration of atmospheric carbon dioxide reached 418 parts per million. How many millions of years ago Earth last saw a concentration like that is a fatuous question at this point. A more pertinent one is what it will do. More CO2 equals more heating but its concentration affects temperature at a lag, so even if emissions were halted now, which isn’t happening, temperatures will continue to climb. One mystery for sea level rise is how the Antarctic ice sheet will react: It could theoretically raise sea level by 57 meters. Now University of Massachusetts Amherst researchers deduced, by comparing the output of climatic/ice sheet/vegetation models with the existing geology, that in the mid-Miocene, the Antarctic ice sheet thinned and retreated significantly but didn’t disappear as heightened rainfall thickened the ice sheet’s interior regions. The report appears in Earth and Planetary Science Letters. We shall see, shan’t we.
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2020 record year for extreme weather in America
Since 1980, the U.S. has suffered 291 weather/climate disasters in which overall damages/costs reached or topped $1 billion, according to the National Centers for Environmental Information. Their total cost exceeded $1.9 trillion, it adds. From 2016 to 2020 there were an average of 16 such events each year, adjusted for the consumer price index, mark you – but the year 2020 set a record with 22 events at a cost of roughly $236 billion in damage. Insurers are begging policyholders to exploit the spring (“the calm before the storm”), which followed the devastating winter, to plan properly, including vis-à-vis insurance. By the way, according to the National Oceanic and Atmospheric Administration, the state that suffered the most billion-plus dollar weather disasters was Texas.
The future of the Texan coast
Apropos Texas: There too the state has warmed by 1 to 1.5 degrees Celsius already, according to the Environmental Protection Agency, and while rainfall has been increasing so far in much of the state, the soil is drier, it warns. And the sea is rising and will do more of that – and not only because of melting ice, but because of land subsidence thanks to groundwater depletion. “If the oceans and atmosphere continue to warm, sea level is likely to rise two to five feet in the next century along much of the Texas coast,” the EPA warns. If not more. And don’t forget that climate change is expected to cause at least some hurricanes to become even stronger. If ever there was a time to plan, this spring sounds like it.