Global Warming and Whipsaw Weather
Perhaps you’ve noticed that we’ve had a record-shattering heat wave across much of North America in recent months, whereas Europe and Asia have experienced an unusually cold winter. That’s to be expected according to a new report on extreme weather published by the Intergovernmental Panel on Climate Change. The report points out that it’s “very likely” that we’ve seen an overall increase in both cold and warm days (and nights) since 1950 due to global warming. Another recent study, published in Nature Climate Change, came to a similar conclusion, noting that the evidence for global warming as the cause of increases in heat waves and precipitation extremes is particularly robust.
Raise Your Glass to Water
March 22nd was World Water Day. Where is the world’s water? You’ve likely heard that oceans hold 97 percent of it. That’s true, but the numbers get even more interesting when you start to consider some of the less voluminous places where water resides. As this story noted, swamps hold four times as much water as the world’s rivers (0.0008 percent versus 0.0002 percent); and the atmosphere holds more than both (0.001 percent). Want to learn about the blue stuff? A new 30-second animation based on data from the GRACE satellites is on display at Times Square through April 22nd. And though Gothamist suspects it may actually be a Van Gogh painting, NASA’s Goddard’s Scientific Visualization Studio has a new visualization (below) of the ocean’s surface currents that’s going viral.
What’s Causing Lake Poyang to Dry?
Poyang Lake in China has seen better days. Once China’s largest lake, it shrunk to just a fraction of its usual size this winter. Scientists are working to understand exactly what’s causing the decline in water levels, but an ongoing drought has surely played a role. The Three Gorges Dam, which is upriver, has likely contributed to the drawdown as well. Remote Sensing of the Environment recently published a study of data from the MODIS instrument that documents the dramatic fluctuation in lake levels between 2000 and 2010. The authors conclude Poyang Lake covered 3,163 square kilometers (1,220 square miles) in August of 2010, but only 714 kilometers (275 square miles) in October of 2010. (In recent months, the size of the lake has dipped to less than 200 square kilometers (77 square miles.) Overall, the scientists found the size of the lake has declined by about 30 square kilometers (12 square miles) a year.
When it Rains it Pours
Xin Lin and Arthur Hou, scientists based at NASA’s Goddard Space Flight Center, recently published a study detailing seasonal and geographical variations in rainfall across the continental United States. By analyzing data from ground radars and rain gauges, they found that although heavy rain events (greater than 10 millimeters (0.4 inches) of rain per hour) only make up up 2.6 percent of total events, they represented 27 percent of the total volume that fell between 2002 and 2009. Light rain events, in contrast, accounted for 65 percent of rain events and 15 percent of the total rain volume.
A Grandfather Speaks Up
James Hansen is sometimes called the grandfather of climate change science, but he also happens to be the grandfather of a pair of youngsters named Sophie and Conner. In the TED talk below, he explains how their birth helped spur him—a self-described “reticent midwestern scientist”—to speak out about the science he’d been studying for decades.