Hot planet: January 2020 was warmest January in 141 years of records, NOAA says

PHOENIX – Last month was Earth’s warmest January on record, the National Oceanic and Atmospheric Administration reports, and that was true in Arizona, where January 2020’s average temperature was 3.2 degrees above the historic average.

Across the United States, it was the fifth warmest January in 141 years of climate records, NOAA reported Feb. 13. Temperatures were above average in the Southwest, it said, and almost the entire East Coast experienced “much above average” temperatures.

The four warmest Januaries documented in the climate record have occurred since 2016, NOAA said, and the 10 warmest all have occurred since 2002.

Although Arizona’s 2020 January temperature rose 3.2 degrees above the historic average temperature, the increases in Phoenix, Tucson and Flagstaff were less than 1 degree.

“We try to look at the longer term,” said Nancy Selover, the state’s climatologist. “And it’s (the temperature) been rising.”

Selover said last month’s temperature rise can be attributed to lower than average precipitation this winter.

“It’s not been a really, really dry winter that we’ve seen in the past, but it’s been a little drier than normal,” Selover said. “We haven’t seen the winter storms come down and dip into the state as much as we would normally see.”

Summer monsoon storms can turn around a dry winter, Selover said, but if the spring ends up being dry, too, Arizona could be looking at a busy wildfire season.

Tracking these trends can be tricky because of spikes in the short term, she said.

“You can always cut up a graph into a bunch of tiny, little pieces and, of course, the temperatures will fluctuate up and down. We try not to do that. We try to look at the long term,” which gives a better understanding of the changes taking place, Selover said.

Average January temperatures in Arizona have been rising since the early 1950s.

NOAA – a Commerce Department agency whose mission is “to understand and predict changes in climate, weather, oceans, and coasts, to share that knowledge and information with others” – said January 2020 marked the 44th consecutive January and the 421st consecutive month with temperatures at least nominally above the 20th-century average. No records for low temperatures were set anywhere, it said.

Asia had the most dramatic increase in temperatures in January, NOAA said, and in Russia, temperature departures were at least 9 degrees. South America recorded its second highest monthly January temperature.

The Northern Hemisphere’s ocean and land temperature rose 2.7 degrees above the historic average, NOAA said. In addition, Arctic sea ice declined 5.3% below the 1981-2010 average and snow cover across the Northern Hemisphere fell below the 1981-2010 average.

This story is part of Elemental: Covering Sustainability, a multimedia collaboration between Cronkite News, Arizona PBS, KJZZ, KPCC, Rocky Mountain PBS and PBS SoCal.

Four Corners Drought Intensified By Human-Induced Warming

The Four Corners drought of 2017 and 2018 caused $3 billion in losses and led the Navajo Nation to issue an emergency drought declaration.

Now, new research in the Bulletin of the American Meteorological Society suggests a sizable portion of the drought’s impacts stemmed from human-induced climate change.

“We’re going to keep seeing temperature rise, meaning we’re going to keep seeing these extreme events, these impacts occurring, and that makes it really important to start thinking about adaptation,” said co-author Emily Williams, a doctoral student at University of California, Santa Barbara.

In addition to UC Santa Barbara colleagues Chris Funk and Shraddhanand Shukla, Daniel McEvoy of the Western Regional Climate Center in Reno, Nevada, contributed to the research.

The Four Corners drought was intensified by the hottest regional temperatures on record, and occurred during a severe meteorological drought.

Unusually high temperatures worsen droughts in the Southwest by reducing snowpack and causing snow to melt earlier, depriving affected areas of seasonal river flows.

They also increase the amount of water the atmosphere can hold, making air “thirstier” and causing it to pull moisture from plants and soil.

According to model simulations, human-induced warming added 2.3 to 3.6 degrees Fahrenheit (1.3 to 2.0 C) to that heat—parching soil and shrinking plant coverage by 18–30 percent and making poor rangeland conditions worse.
It also drained away 20 percent of potential snowpack meltwater.

Williams said events like these reveal climate change already at work.

“And this drought, which hurt so much of the interior of the U.S., is one of those examples of what climate change looks like in the here and now,” she said.

As available water is exhausted, an additional feedback between land and water can occur: As evaporation, which absorbs latent heat and cools the area, becomes impossible, sensible heat can climb even higher.

“If this is happening in a really dry environment and there’s no more moisture in the soil that will then lead to even greater temperature rise,” said Williams.

Because the study did not model such effects, its results likely reflect a conservative estimate of the impacts of human-induced warming.