Climate Change

A scientific look at global climate changes.

Welcome to the Weather Underground's new Climate Change page!
We're just getting started, so keep checking back over the next few months for new additions.

	Monthly Feature

About Glaciers

Glaciers exist on all the continents of the world except Australia. Most of the world's glaciers are found near the North and South Poles (for more information about Arctic and Antarctic glaciers, please see our pages on Greenland and Antarctica). A large number of glaciers, however, are found in mid-latitude and tropical regions wherever the right conditions exist.

Glaciers exert a significant influence on a landscape. As glaciers move across the terrain, they pick up rock and debris, carve valleys (see Figure 1), and create landforms. Flowing glaciers erode and scour the ground beneath and to the sides of them. These rivers of ice also pick up boulders, soil, trees, and other debris and carry it along in their flow. Once the glacier begins its retreat, however, this material is deposited wherever the glacier.s ice melts. Kettle lakes are formed when large chunks of ice fall off of retreating glaciers and melt, filling depressions in the ground. For more information on glacial formations, see the links below, which will connect you to some sites with photos and descriptions.

There are two main types of glaciers — valley and continental. Valley or alpine glaciers form in mountainous regions where movement is inhibited by valley walls. Continental glaciers, also known as ice sheets, are "dome-shaped mass[es] of glacier ice… greater than 50,000 square kilometers (12 million acres) (e.g., the Greenland and Antarctic ice sheets)" (NSICD).

	Latest Monthly Climate Trends

		Departure of temperature from average for last month (updated by the 17th of each month) from the National Climatic Data Center.
		Average October arctic sea ice coverage as observed by satellites between 1979 and 2008. Image credit: National Snow and Ice Data Center.

Monthly Summary (Updated between the 16th and 19th of each month)

October 2008

The planet continues to stay extremely warm this year, though no record warm months have been recorded in 2008. October 2008 came the closest--it was the 2nd warmest October for the the globe on record, according to statistics released by the National Climatic Data Center. These statistics have been corrected for a widely reported error that was discovered earlier this month. Over land areas, it was the warmest October on record. The period January through October was the 9th warmest such period on record. Records extend back 129 years, to 1880. Much of the unusual warmth occurred over Asia, Australia, and Eastern Europe (Figure 1). According to the Australian Bureau of Meteorology, October 2008 was an exceptionally dry month in central and southeastern Australia, ranking as the driest October on record for South Australia, second driest for Tasmania, and third driest for Victoria.

There is neither a La Niña nor El Niño at present, and neutral conditions now prevail in the tropical Eastern Pacific. There is no indication that this will change in coming months, and most of the computer climate models forecast a continuation of neutral conditions over the next three months.

For the contiguous U.S., October was pretty ordinary. It was the 44th coolest and 51st driest October since 1895. October was the 7th wettest on record for the West North Central U.S. and the 17th driest for the Northwest U.S.

Sea ice extent

October 2008 Northern Hemisphere sea ice extent was the third lowest on record for the month of October, 34% below the mean from 1979-2000, according to the National Snow and Ice Data Center. This is 9.5% below the 1979-2000 average. The record October low was set in 2007.

Climate Change Blogs:

Importance of Justification

Featuring Dr. Ricky Rood

Justifying Climate Science: In May I attended the World Modeling Summit for Climate Prediction at the European Center for Medium-range Weather Forecasts. This summit received some press coverage, most notably in Nature. At this summit were a number of themes that have been around for years, notably, big computers, extremely high-resolution models, the relationship between weather and climate, and frustration.In the 1990’s I worked for NASA, and there were these c...

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Unexpected ocean cooling result found to be an error

Featuring Dr. Jeff Masters

Since the publication in 2006 of the paper, Recent cooling of the upper ocean, climate scientists have been scratching their heads, trying to figure out why the upper layer of the ocean had cooled from 2004-2006. Since the oceans absorb more than 80% of the heat from global warming, we should expect to see the oceans heating up if the globe is warming. Climate skeptics pointed to the result as evidence that the planet was not warming after all, although surface and satellite measurements showed that the year 2005 was the warmest or second warmest year on record for the surface of the globe. Now, the explanation for this apparent cooling of the oceans has been resolved--key measurements made by submersible robot buoys and that indicated the ocean was cooling were found to be in error.

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	Iconic Image Gallery

The Iconic Image Gallery is a collection of figures that show important climactic trends. Click on each for a full-sized version of the image, the message that it contains, and a discussion of what makes it 'iconic'. Keep checking back -- we'll be posting additional images soon!


Keeling CO2	Vostok ice cores

Mitigation and Adaptation	Forcing

The Cryosphere: Snow and Ice