What role did climate change play in recent catastrophic hurricanes? What’s going on in the Pacific Ocean? How can we tell what sea level looked like in the past? Find answers to these questions and more in this month’s climate science round-up.
The oft-asked question is whether human-caused climate change caused these storms. However, this is the wrong way of looking at it. Climate change reflects a change in the background state in which all weather exists. It does not, by itself, cause hurricanes, but it can certainly make a hurricane’s impact worse.
Scientists now routinely assess how global warming has affected extreme events, like the recent hurricanes. While these studies use a variety of approaches, they all consider two worlds: one, our current world with human-caused increases in greenhouse gases and resulting warming; and two, another world without current levels of greenhouse-gas-induced warming.
For the entire globe, both August and the summer season were the third warmest on record. The global temperature year-to-date was 1.58 degrees F above the average. The average Arctic sea ice extent for August was 24.3 percent below the 1981-2010 average, while the average Antarctic sea ice extent was 3.6 percent below average.
Since late April, sea level around Hawaii has been so high that measurements are breaking records. In part, these record highs relate to the variability related to the El Niño Southern Oscillation, which has recently trended toward La Niña. In La Niña years, sea levels across the western Pacific rise higher than normal. That, combined with localized ocean eddies and global sea level rise due to climate change, has caused anomalously high sea levels. This summer, the Western Pacific has also seen lower-than-normal rainfall and warmer-than-average sea surface temperatures.
Researchers from NASA and the University of California, Irvine, have reported the first detection of sea level “fingerprints” in ocean observations, detectable patterns of sea level variability around the world resulting from changes in water storage on Earth’s continents and in the mass of ice sheets. The results will give scientists confidence they can use these data to determine how much the sea level will rise at any point on the global ocean as a result of glacier ice melt.
Biologists are racing to secure a visit to a newly revealed region of the Southern Ocean as soon as it is safe to sail there. One of the largest icebergs ever recorded broke free from the Larsen C ice shelf on the Antarctic Peninsula in July. As it moves away into the Weddell Sea, it will expose 5,800 square kilometers of seafloor that have been shielded by ice for up to 120,000 years. If researchers can get to the area quickly enough, they’ll have the chance to study the ecosystem beneath before the loss of the ice causes it to change.
Tropical forests are adding more carbon dioxide to the atmosphere than they’re removing, according to a new study that estimates the world’s lush canopies emit more CO2 than all of America’s cars and trucks. The silver lining, the researchers say, is that tropical forests have untapped potential to act as carbon sinks through better conservation and land management.
Scientists have just documented an unexpected process occurring in the air over the Antarctic ice sheet: The wind is causing snowflakes to vaporize — literally — before they hit the ground. This means less snow may be accumulating on the continent’s surface than scientists thought. And that could change researchers’ understanding of the way climate change affects the ice sheet, including their estimates of future sea-level rise.
Sea stars are basically nature’s own X-Men. Some species have the ability to regenerate, growing a whole new body from a severed limb. But on the West Coast, a newly identified mutation is giving some sea stars a whole new power — one that may help them survive long into the future.
Edited by Elizabeth Weinberg. Have a climate science tip? Send it to firstname.lastname@example.org.