Climate Change’s Calling Card in 2014: Heat

By Brian Kahn

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Editor’s Note: This is one in a series of stories in which we look back at key issues and events of 2014 and why they will continue to make headlines in 2015.

Global warming and extreme heat continued filling the airwaves in 2014 and it’s likely that the hits will just keep coming in 2015 and beyond.

This year is virtually guaranteed to go down as the world’s hottest on record. But it’s not just one hot year we’re talking about. It’s a staggering list.

Consider that the 15 hottest years on record have all come since 1997. Or that this will be the third straight decade to break the mark for global temps. And that it’s been 358 months since the planet had a cooler-than-average month, and more than 100 years since we last had a record-cold month.LOOKING BACK AT 2014
AND AHEAD TO 2015Monday
Fate of Earth’s Ice Comes

Tuesday
Ocean Warming:

Wednesday
U.S. at Brink of Turning
Point in Energy

Thursday
Climate Change’s Calling

Friday
Climate Change's Evolving

None of this should come as a surprise. As the world warms, record heat is climate change’s calling card. As a new year turns over, a number of signs point to 2015 following in this year’s toasty footsteps. This includes the possibility of a weak El Niño further raising global temperatures and clues from coral reefs indicating a heat spike could be looming in the near future.

Numbers only tell part of the story. The impacts of rising temperatures are what really matter. The oceans are warming, likely storing the planet’s excess heat (though that can’t continue indefinitely). The polar regions are melting, raising sea levels. Increased heat fuels wildfires and exacerbates drought, which feeds into water and food scarcity, potentially igniting regional conflicts. Public health could also be threatened by heat waves and insect-borne diseases that thrive in the heat.

Yet global warming is not monolithic. Striking changes are afoot in the Arctic, where temperatures are warming twice as fast as the rest of the globe, and in Australia, whose isolation offers scientists a venue to examine the impacts of extreme heat more closely.

In many ways, that continent is a poster child for global warming. After having its hottest year on record in 2013 — which research has tied directly to climate change — heat waves baked the country in January 2014. Then April capped Australia’s warmest two-year period on record.

“They’ve left behind the climate that they used to have,” NOAA research meteorologist Thomas Knutson told Climate Central earlier this year.

Back in the U.S., the country is divided by red states and blue states, and not just politically.

California is on track to smash its warmest year on record. In an age where temperature records are usually broken by one-tenth or one-hundredth of a degree, the state was running 4.1°F above its long-term average, besting its previous record set in 1934 by 1.7°F. A swath of other western states from Arizona to Washington are also looking at one of their five hottest years on record. The western U.S. could see temperatures up to 8°F warmer by 2100, putting this year’s top 5 finish to shame.

In contrast, a number of states in the Midwest are on track for their top 10 coldest years  thanks to the much maligned polar vortex. If history is any lesson, this pattern could become the norm as the world warms. A finding earlier this year showed that 4,000 years ago, temperature gradients across the globe were similar to what they are now and contributed to a kinky jet stream, a fast moving river of air that drives weather around the globe.

Having a lot of twists and turns in the jet stream can lock weather patterns into place for long periods of time, just as it did this year in the U.S. with the cold-East, warm-West divide.

The difference is that 4,000 years ago, the pattern was brought on by natural shifts. The current pattern, according to scientists, has a stronger connection to greenhouse gases with extreme warming in the Arctic reducing the temperature gradient from the pole to the equator. There’s little doubt that a wavier jet stream can drive more extreme weather including heat, but the role of Arctic warming in causing extreme weather in mid-latitudes is still very much up for debate in 2015 and beyond.

One thing not up for debate is the fact that human activity is a significant driver of global warming, with carbon dioxide emissions at the heart of the issue. Those emissions are not slowing and with atmospheric concentrations of CO2 likely to reach 400 parts per million even earlier this year than last, climate change’s hit parade will top the charts for all the new years ahead.

Best of Extreme Heat Coverage From 2014: 
Climate Change Is Increasing Extreme Heat Globally
Hot West, Cold East May be the Norm as World Warms
Since First Earth Day, U.S. Temps Marching Upward
Here’s How Much U.S. Summers Have Warmed Since 1970
Summertime Blues? U.S. Seeing Red as Temps Rise
1,001 Blistering Future Summers
87 Cities, 4 Scenarios and 1 Really Hot Future
Hot and Getting Hotter: Heat Islands Cooking U.S. Cities
Climate Change Ups Odds of a Southwest Megadrought
Another Year, Another Record High for Greenhouse Gases