Plan B Forum

Climate change is having significant financial, ecological and human health impacts across the US, according to a new report.

The third National Climate Assessment, released by the White House, says the number and strength of extreme weather events have increased over the past 50 years.

Infrastructure is being damaged by sea level rise, downpours and extreme heat.

The report says these impacts are likely to worsen in the coming decades.

Coming hot on the heels of the trio of reports from the Intergovernmental Panel on Climate Change (IPCC), the assessment re-iterates the finding that climate change is real, and "driven primarily by human activity".

A key element driving this conclusion is the observed evidence on extreme weather events such as heavy downpours of rain.

Between 1958 and 2012, the amount of precipitation falling in very heavy events increased by 71% in New England and the north east, while in the drier West it went up by just 5%.

"There is no equivocation," said lead author Prof Gary Yohe from Wesleyan University.

"It is fundamentally the pace of observations of extreme weather that makes it clear it is not natural variability."

The report suggests that it is not just wet events that are becoming more common. The human influence on climate has "roughly doubled the probability of extreme heat events", it says.

The authors point to the record-breaking summer temperatures in Texas and Oklahoma in 2011, where even during the night the mercury continued to soar.

If there’s one thing you should get used to with climate change—apart from the heat waves, droughts, and intense storms—it’s hot, uncomfortable nights. Worldwide, there will be somewhere around two weeks of higher nighttime low temperatures. In some places, winter nights may be unseasonable warm, or in others summer nights could grow more sweltering and sleepless.

But it’s not just our comfort that’s at stake. Plants are uniquely sensitive to nighttime low temperatures. If they’re too high, plant respiration rates tend to increase. (Yes, plants respire just like us. Unlike us, they’re able to grow without eating because, during a typical day, the rate of photosynthesis greatly outpaces the rate of respiration, meaning they’re making more food than they are consuming.) When respiration rates rise in plants, they consume more of the carbohydrates they made through photosynthesis during the day. With less energy available, they might grow more slowly or put less energy into producing seeds. It happens that many staple crops, like rice and corn, are seeds, so warm nights are one way climate change could slash crop harvests.

Not only will more people be going to bed sweating, they’ll be doing so on empty stomachs.