The United States is getting warmer and parts of it are getting wetter, according to weather data released on Tuesday by the National Oceanic and Atmospheric Administration (NOAA).
NOAA, a US scientific agency that tracks weather data, has released a “new normals” set of data that tracks changes in the US climate. The report details data from 1991 to 2020 and updates what is defined as climate normals over the past 30-year period – allowing weather conditions to be put into “historical context”.
The latest data set which replaces 1981-2010 normals shows a rise in average temperature.
“NOAA’s Climate Normals provide a baseline to compare yesterday’s weather and tomorrow’s forecast to a standard for each location and time of year,” said Mike Palecki, project manager for NOAA’s 1991 to 2020 Climate Normals according to the NOAA website.
The data goes back to 1901, and the “influence of long-term global warming is obvious”, a summary of the information says.
The newest batch of normals will also include data over 15 years.
Climate change can have major effects on sections of the economy such as agriculture, which relies on “certain seasonal cycles” for successful crops. These cycles can be changed by shifts in temperature. The data also shows planting zones for crops have moved north in a “clear signal that normal overnight low temperatures across the country were warmer than they used to be”.
The effects are not standard across all regions. Some, such as parts of the Pacific Northwest like Oregon, show gradual, consistent temperature increases.
Other regions, like much of the Gulf Coast, show “normal annual temperatures were actually warmer than the 20th-century average in the first four sets of normals. Beginning with the 1941-70 normals, they reverted, with normal annual temperature growing increasingly cooler over the next two periods. That cooling pattern began to weaken with the 1971-2000 normals, and it has all but disappeared today.
The US is growing wetter, too. The NOAA data notes the difficulty of tracking precipitation, as it varies greatly from region to region across time.
But its data show regions of the US that were “12.5 percent or more wetter than the 20th-century average” comprise much of the country. The Southwest, however, is getting drier.
The data is collected by “almost 15,000 stations with precipitation normals and more than 7,300 stations with temperature normals” according to a NOAA presentation (PDF) outlining the data.
Scientists have long warned of the danger of increased temperatures. Hotter weather tends to make stronger natural disasters like hurricanes, which have battered the US in recent years.
Globally, scientists worry about the increasing rate at which polar ice caps are melting, which they expect to increase sea levels and speed climate change by releasing greenhouses gases trapped in the ice.
The administration of US President Joe Biden has set ambitious goals to confront climate change.
The administration announced at its Earth Day summit last month that it wants to cut national greenhouse gas emissions by 50-52 percent below 2005 levels by 2030.
NOAA promised to continue documenting the changes.