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Sandy Tops List of 2012 Extreme Weather & Climate Events

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No. 4  Steamy Arctic Events Alarm Climate Scientists

The continental U.S. had its warmest year on record in 2012, but things were unprecedentedly steamy at the top of the globe as well. And what transpired there -- from a falling snow cover, an alarming rate of melting of Greenland’s ice cap, and a melt back of Arctic sea ice -- was worrisome to climate scientists, who have long predicted that climate change would strike the Arctic faster and harder than the rest of the globe.

During the spring, snow cover across North America and Eurasia dropped to the lowest level ever seen. A few months later in July, fully 97 percent of Greenland’s ice cap -- which covers most of that enormous island -- experienced at least some surface melting. That hasn’t happened since at least the 1800s. During that same month, a glacier in northern Greenland shed a slab of ice twice as big as Manhattan Island. And finally in August, the ice that covers the Arctic Ocean melted back more than it has since satellite observations began in the 1970s, and kept on dropping right through mid-September.

But the loss of sea ice was perhaps the most startling news.

Late-summer sea ice in the Arctic Ocean has been on a downward spiral since the late 1970s, but the downward trend isn’t perfectly smooth. Some years actually see more ice than the year before, as wind patterns and ocean currents in a given summer might enhance or hold back that season’s melting. However, the long-term trend has been toward diminished summer sea ice cover. Studies have shown that this trend is due to a combination of manmade climate change and natural climate variability.

In 2012, ice coverage reached a new low — and not by a small amount, either. As of September 16, according to the National Snow and Ice Data Center (NSIDC), just 1.32 million square miles (2.41 million square kilometers) of ice were left floating in the Arctic Ocean, a whopping 18 percent less than the previous record of 1.61 million square miles (4.17 million square kilometers), set in 2007. The amount of sea ice that melted between March and September, the NSIDC said, would be enough to cover Canada and Texas, combined. The melt rate was so fast, in fact, that the old record was shattered weeks before the new low was reached.

Graphic showing how thick multiyear ice is being replaced by thin, first-year ice.
Click on the image for a larger version. Credit: NSIDC. 

NSIDC scientist Julienne Stroeve told Climate Central that’s especially significant because “the 2007 minimum was, in large part, driven by [unusual weather patterns], and this summer we shattered the 2007 minimum under more normal summer circulation patterns.”

It’s all consistent, however, with scientists’ understanding of the role sea ice plays in the Arctic Ocean and the global climate. When it’s there, the ice’s bright, white surface reflects sunlight back into space. When it melts, the darker sea water it exposes absorbs more of that light, heating the ocean and the air above. When the ice refreezes in the fall and winter, it’s thinner, and prone to melting even more easily in future seasons, exposing even more water and setting up a feedback loop that could leave the Arctic Ocean seasonally ice-free by later this century. Computer models predict this may occur by 2050, and some scientists think it will happen even earlier.

The side effects of declining Arctic sea ice are already being seen, and are occurring faster than scientists expected just a few years ago. To start with, some scientists think that warmer Arctic sea and air temperatures are now influencing the jet stream in the northern hemisphere, leading to more extreme weather events.

A wavier jet stream that features more frequent “blocking” events, or stuck weather patterns, could be leading, paradoxically, to stormier winters in the U.S. and Europe. This is an area of active scientific research, and many climate scientists remain skeptical that Arctic sea ice loss has already started to change the weather in lower latitudes, although it’s widely recognized that melting sea ice is warming the Arctic climate.

Arctic sea ice cover off Ellsmere Island in Canada.
Click on the image for a larger version. Credit: Michael D. Lemonick.

In addition, the extra heat building in the Arctic is accelerating the pace of global warming overall. Another problem is that warm air is already starting to melt the permafrost that pervades the soil in northern Alaska, Canada and Siberia. That could release carbon from organic matter that has been frozen for many thousands of years — yet another feedback that could accelerate global climate change.

This year also saw a record low spring snow cover in North America and Eurasia, and the rate of snow cover loss in springtime has been even faster than the rate of sea ice loss. The loss of spring snow cover affects the length of the growing season, the timing and dynamics of spring river runoff, permafrost thawing, and wildlife populations. This was the third time in five years that North America saw a record-low spring snow cover, and the fifth year in a row that Eurasia has. Warmer air temperatures have played a large role in driving this trend, since during the past decade no part of the Arctic has been cooler than the 30-year average.

Warmer ocean water, meanwhile, is destabilizing glaciers that drain Greenland’s massive ice cap, which holds enough fresh water to raise sea level by more than 20 feet. Warm air over the Arctic in 2012 triggered the most widespread surface melt on the Greenland ice cap on record.  

All the melting has also encouraged an increase in both shipping and oil exploration in Arctic waters, threatening to bring pollution to these formerly pristine waters — and also posing new risks to the men and women living and working there.

Related Content
Ongoing Coverage of the Planet's Polar Regions
Visualizing 2012’s Record Arctic Sea Ice Melt
Forget the Melting Arctic, Sea Ice in Antarctica is Growing!
It’s Official: Arctic Sea Ice Shatters Record Low
A Closer Look at Arctic Sea Ice Melt and Extreme Weather
‘Astonishing’ Ice Melt May Lead to More Extreme Winters
Greenland Glacier Sheds Two Manhattans' Worth of Ice 

(Read each of the Top 10 events by following the page links below)

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Comments

By Emma H. (Rockwood, Ontario, Canada)
on December 31st, 2012

If the first step to survive climate change is interest, the second is knowledge. Which makes it worth considering that the place where we gain much of our common knowledge is school.  Unfortunately for the issue of climate change, school is focused on the economy, on creating good participants in the global marketplace, as well as good consumers who measure their success by their material gains.  And who are encouraged to spend more than they earn through easy credit and resulting debt.

What would it take for Americans to demand that education contribute to creating a sustainable future? It’s not a simple or easy change from our current educational aspirations.  But it’s one that might make it possible to work together and make the profound changes that will be needed to, first of all, lessen fossil fuel use, and then live well with less of the energy and petroleum products we’re addicted to.

We can create more local economies, regain lost skills, build local renewable energy systems, build local businesses, improve batteries needed to store power from intermittent wind and solar sources, begin a transition to a less lethal kind of culture.  We need to do it ourselves because our leaders are far too swayed by powerful fossil fuel and financial industries who invest hugely in maintaining the status quo.  But every decision we make, individually and collectively, can move the future to a new place.  Every product we buy comes from a company with policies we can support or reject.  Every mile we drive generates carbon dioxide - every mile we walk or bike - or don’t travel - doesn’t.  Local food and good insulation save energy, organic food doesn’t use fossil-fuel based chemicals (pesticides, fertilizers, hericides).  Growing food and making things and playing music are highly satisfying skills that we have been educated to give up so we need to buy them “in the marketplace.”  But we could take them back. 

If we don’t begin to think more self-sufficiently, and with more awareness of the connections betwween fossil fuels and climate change, we’ll continue to see the weather become more violent, food prices rise, the cost of living soar, and “homeland security” come to mean the degree of climate stability we need. 

We were only able to become an agricultural society because of the last ten thousand years of stable climate.  If we continue to exacerbate climate change, we risk losing nothing less than the basis of civilization.  Education may be our only chance to bring about a large-scale turnaround. It can only happen if we work - hard - to make it happen.

We need to make our schools places of learning how to become a sustainable civilization.  If this is a new idea to you, do some browsing on “sustainability education.”

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