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 August 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)

August 2008

August 2008 was the 9th warmest August for the the globe on record, according to statistics released by the National Climatic Data Center. The period June, July and August (Northern Hemispher Summer, Souther Hemisphere winter), was the tenth warmest such period on record. There is neither a La Niña nor El Niñno at present, and neutral conditions now prevail in the tropical Eastern Pacific. For the contiguous U.S., August was the 39th warmest and 9th wettest August since 1895.

Sea ice extent

August 2008 Northern Hemisphere sea ice extent was the second lowest on record for the month of August, 21% below the mean from 1979-2000, according to the National Snow and Ice Data Center. During a portion of August the rate of sea ice loss was the most rapid on record.

Climate Change Blogs:

Climate Predictions and the Sun

Featuring Dr. Ricky Rood

The Sun (5): This is the last of a series on the Sun in the Earth-Sun climate system. The first four entries are linked at the end. I want to first thank both Judith Lean at the Naval Research Laboratory and David Rind of NASA for their introduction to the current literature and insights into the problem. Lean and Rind have a new paper How natural and anthropogenic influences alter global and regional surface temperatures: 1889 to 2006. This appears in Geophysi...

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The tornado season of 2008: climate change to blame?

Featuring Dr. Jeff Masters

Let's be clear that human-caused climate change is occurring, and will significantly affect nearly all aspects of weather and climate in the decades to come. However, many of these changes will be so small or gradual that they will not become detectable until many decades hence, since there is a large natural variability in weather. As I noted in my February blog, Are tornadoes getting stronger and more frequent?, there is new research that predicts that we may see an increase in the severe thunderstorms that spawn tornadoes by the end of the century.

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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