Map of the Day: The State of a Warming America

Temperatures rose in each of the continental 48 states since 1970.

Sweating more than usual this spring? You're not alone. In the United States, the first five months of 2012 have been the warmest on record. More than 100 cities out of 150 recorded have seen their warmest recorded temperatures.

Just a quick glance at this chart gives a good insight into how steamy our cities have been so far this year. But while this year is off-the charts it's not a surprise. We've seen temperatures on the rise for decades, as a new report from Climate Central illustrates.

Here's the temperature change from 1912-2011:

And here's how the temperatures have changed since 1970:

The report discusses the disturbing trends:

  • Over the past 100 years, the top 10 states warmed 60 times faster than the bottom 10 (0.26°F per decade vs. 0.004°F per decade), when looking at average mean temperatures. During this timeframe, 45 states showed warming trends, although 21 were not statistically significant. Three states experienced a slight cooling trend.
  • Since 1970, warming began accelerating everywhere. The speed of warming across the lower 48 more than tripled, from 0.127°F per decade over the 100-year period, to 0.435°F per decade since 1970, while the gap between the fast and slowly warming states narrowed significantly; the 10 fastest warming states heated up just twice as fast, not 60 times as fast as the 10 slowest warming states (0.60°F vs. 0.30°F per decade). Over the past 42 years 17 states warmed more than half a degree F per decade.
  • The states that have warmed the most — whether you look at the past 100 years or just the past 40 — include northern-tier states from Minnesota to Maine and the Southwest, particularly Arizona and New Mexico. Places that have warmed the least include Southeast states, like Florida, Alabama, Georgia and South Carolina, along with parts of the central Midwest, like Iowa and Nebraska.

Or the take away fact: Temperatures rose in each of the continental 48 states since 1970. 

"The Southwest and North Central and Northeastern states are clearly warming faster than the rest of the country," said report author Claudia Tebaldi. “As warming continues, future droughts could be hotter and more severe, seasons will be altered, and the risk of wildfires will increase significantly, making summers like 2011 increasingly common."

Is your city prepared for the effects of climate change?

About the Author