Events like record-setting heat, extreme rainfall and drought will happen more frequently around the world even if global climate targets are met, new research suggests.
And missing those targets could make the risk even worse.
If global temperatures rise by up to 3 degrees Celsius above their preindustrial levels, the risk of extreme events could grow by as much as fivefold in certain parts of the world. Overall, up to 60 percent of locations across North America, Europe, East Asia and parts of southern South America would likely see at least a threefold increase in various extreme events, according to a study published yesterday in the journal Science Advances.
The results paint a worrying picture of the future, given that the pledges world nations have submitted under the Paris Agreement are likely still not enough to keep global temperatures within the 2 C threshold envisioned by the accord. Experts suggest that the pledges may put the world on track to warm by about 3 C, unless significantly greater climate action is promised—and soon.
"In addition to not meeting the global temperature target, those commitments also imply substantial increase in the probability of record-setting events," said Noah Diffenbaugh, a Stanford University climate researcher and the new study's lead author. "Not only hot events but wet events, and also in other regions of the world, dry events as well."
The research used historical data—mainly from North American, Europe and East Asia—and an ensemble of climate models to analyze the past and future risk of various extreme hot, wet and dry events, including the highest daytime and nighttime temperatures, mildest low temperatures, wettest days, and longest dry spells. Large areas of the world have already experienced an increase in extreme events, they found—and these risks will only worsen as the climate continues to warm.
Heat records are likely to be among the most sensitive to future climate change. Record-breaking nighttime temperatures have already been increasing across 90 percent of the studied areas, the research suggests, and these records may increase by at least fivefold across half of Europe and a quarter of East Asia. Extreme wet events and milder cold spells are also expected to increase throughout the world, and extreme dry events will see an uptick in certain regions, mainly in the midlatitudes.
Strengthening the Paris pledges could help significantly reduce the risks of extreme climate events, the new research suggests, although it warns that these events will still become more frequent in the future, even if temperature increases stay under 2 C. Altogether, the research suggests that up to 90 percent of the studied areas may experience some increase in extremes—maybe not three- or fivefold in most places, as in more severe climate scenarios, but an increase over the present day.
"The aspirational U.N. targets are both likely to substantially reduce the risk of unprecedented extreme events, but still carry an increased risk relative to the present," Diffenbaugh said.
The study's findings focus mainly on North America, Europe and East Asia, where the historical data were the strongest. But a model-only analysis of the rest of the world—including large regions of South America, Africa and Australia—suggested that these places will likely see similar, if not larger, increases in extreme events, as well.
The findings, overall, carry a double warning. First, even with aggressive climate action, extreme climate events are likely to increase throughout much of the world—and human societies should brace themselves for that future, no matter what. But those mitigation efforts are still sorely needed, the research also suggests. Without them, the risks could be far more intense.
Reprinted from Climatewire with permission from E&E News. E&E provides daily coverage of essential energy and environmental news at www.eenews.net.