The first Earth Day was held 45 years ago, at a time when air and water pollution were the nation's major environmental concerns. This was shortly before the EPA existed, and the day and movement associated with it helped galvanize public support for the enactment of bedrock environmental laws like the Clean Water Act and Clean Air Act.

Now, though, while we've made tremendous progress in cleaning up the nation's air and water and protecting public lands, a broader challenge that requires a host of innovative solutions looms: global warming.

Forty-five years is a long enough period of time to reliably view climate trends, and over this period the average temperatures in the U.S. have increased considerably. The folks at Climate Central, a climate news and research organization, have put together an interactive showing warming trends for each of the lower 48 states.

According to Climate Central's research, average temperatures across most of the continental U.S. have been increasing at a rate of about 0.13 degrees Fahrenheit per decade between 1910-2014. This is in line with the overall increase in global average temperatures due in large part to manmade greenhouse gas emission.

However, since 1970, most states have warmed at a much faster rate, as has the globe. On average, temperatures in the lower 48 states have been rising at a rate of 0.45 degrees Fahrenheit per decade since 1970. New Mexico wins the title for the fastest-warming state since 1970, with a warming rate of 0.63 degrees Fahrenheit. Vermont, Arizona, Delaware and New Jersey are warming nearly as fast, Climate Central says, and "all these states are warming about twice as fast as the global average."

The slowest-warming states are Iowa, Alabama, Missouri, and Georgia, which are warming at just under 0.3°F per decade since 1970. However, they are still on pace with the global average temperature trends.

Climate change in the U.S. is already having adverse impacts on people and the ecosystems they depend on, from sea level rise causing problems in South Florida to more heavy precipitation events (rainstorms and snowstorms) in the Northeast.