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March Was the 10th Warmest Month on Record Despite Record Cold in the US

What was balancing out the record cold in Europe and parts of North America?
Photo: Chris Hawes/Flickr

Despite headlines proclaiming that March's cold weather setting many new records across Europe, 2000 new cold records being set across the United States, and that March 2013 was 13 degrees colder than the previous year in the US, being the 59th coldest March since national records began in 1871, the global picture was very different.

The latest data from NOAA shows that, for the planet as a whole, March 2013 was the 10th warmest month on record, tying with 2006.

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Globally, the combined average land and ocean surface temperature was 0.58°C above the 20th century average. Breaking that out, the global land surface temperature was 1.06°C above average (11th warmest), with the ocean surface temperature being 0.41°C above average (9th warmest). For the first three months of the year temperatures were also 0.58°C above average, making in the eighth warmest first quarter of the year.

What was balancing out the record cold in Europe and parts of North America?

The NOAA report says most of China saw record warmth, at least 5°C above average, with the tropics in general being 1.18°C warmer than normal. Northern Africa and northern South America, as well as northern Australia were also hotter than usual. Australia as a whole continued setting records: March was the eighth month in a row with every state and territory having above-average temperatures.

Image: NOAA

Looking at the state of warming beyond modern record keeping—which for most places dates back at the latest to the mid-19th century—research published in Nature Geoscience, conducted by the Earth Institute at Columbia University, shows that the Earth's climate warmed more in the last three decades of the 20th century than it had in the past 1400 years.

Looking at usual sources of climate data such as tree rings, ice cores, lake and ocean sediments, as well as instrument records from more recent time periods, the research found that over the past two millennia the "most consistent trend across all regions…was long-term cooling, likely caused by a rise in volcanic activity, decrease in solar irradiance, changes in land-surface vegetation, and slow variations in the Earth's orbit."

But the start of industrialization saw that cooling come to an end, everywhere but Antarctica. Over the 20th century, the report found, warming happened twice as quickly on average in the Northern Hemisphere than in the Southern.

On average, surface temperatures have warmed roughly 0.8°C in the past century, with most of that warming happening since the 1970s. Nevertheless, the data shows that there was a brief time period in Europe, from 21-80 CE, when temperatures were actually higher than from 1971-2000.

Temperatures are unequivocally expected to continue rising: It's all but 100 percent certain that current levels of greenhouse gas emissions will send us well past the critical 2°C warming threshold.

A glimpse of what really catastrophic warming could look like, combined with a lack of rain and dry soil: The Earth Institute research examined the July 2003 heat wave in Europe, which killed 70,000 people, and found it was the continent's hottest summer in two millennia. Temperatures in France at the time were up to 10°C hotter than normal.