HOT ENOUGH FOR YOU?

By Pam Eastlick

Welcome to The Deep science and technology column where we cover topics from the deep sea to deep space and beyond.

Although I did a column about global warming last month, it may be time to do another one because the climate statistics for 2011 are in and they’re a little scary. According to NASA scientist, the global average surface temperature in 2011 was the ninth warmest since 1880. And if that’s not scary enough for you, nine of the 10 warmest years in the modern meteorological record have occurred since the year 2000.

According to data provided by NASA’s Goddard Institute for Space Studies (GISS) in New York, which monitors global surface temperatures on an ongoing basis, the difference between 2011 and the warmest year in the GISS record (2010) is 0.22 degrees F (0.12 C). This underscores the emphasis scientists put on the long-term trend of global temperature rise. Because of the large natural variability of climate, scientists don’t expect temperatures to rise consistently year after year. However, they do expect a continuing temperature rise over decades.

The first 11 years of the 21st century experienced notably higher temperatures compared to the middle and late 20th century. The only year from the 20th century in the top 10 warmest years on record is 1998.

Scientists think that today’s higher temperatures are caused by large amounts of greenhouse gases (especially carbon dioxide) that are present in the atmosphere. These gases absorb heat emitted by Earth and release that energy into the atmosphere rather than allowing it to escape to space. As their atmospheric concentration has increased, the amount of energy "trapped" by these gases has led to higher temperatures.

The carbon dioxide level in the atmosphere was about 285 parts per million in 1880, when the GISS global temperature record begins. By 1960, the average concentration had risen to about 315 parts per million. Today it exceeds 390 parts per million and continues to rise at an accelerating pace.

The NASA scientists also expect record-breaking global average temperature in the next two to three years because solar activity is on the upswing and the next El Niño will increase tropical Pacific temperatures. The warmest years on record were 2005 and 2010, in a virtual tie. They say that it won’t take a very strong El Niño to push temperatures above the record set in 2010.

So what is all that heat causing? Well, for one thing, Greenland is beginning to bob up like a cork because the ice that covers it is melting. The record temperatures in 2010 melted 100 billion tons of ice off Greenland and large portions of the island’s bedrock rose almost an inch in response.

Every year as the Greenland ice sheet melts, the rocky coast rises. Some GPS stations around Greenland routinely detect uplift of 15 mm (0.59 inches) or more, year after year. But the temperature spike in 2010 lifted the bedrock a detectably higher amount over a short five-month period — as high as 20 mm (0.79 inches) in some locations.

While it’s true that most of the melting is happening in the southern half of Greenland, the GPS stations that scientist have installed in the exposed bedrock around the ice sheet margins along the Greenland coast have recorded unprecedented uplift in the land. And if it’s happening in Greenland, you can bet it’s happening in Canada and Russia too. And it’s only going to accelerate.

What does it mean for you? Who knows, but I’m beginning to be afraid that all the negative effects are going to start happening while I’m still around instead of long after I’m gone.

Hot enough for you?