Global Warming Fast Facts

Global warming, or climate change, is a subject that shows no sign of cooling down. Here's the lowdown on why it's happening, what's causing it, and how it might change the planet. Global warming is coming...

Is It Happening?

Yes. Earth is already showing many signs of worldwide climate change.

• Average temperatures have climbed 1.4 degrees Fahrenheit (0.8 degree Celsius) around the world since 1880, much of this in recent decades, according to NASA's Goddard Institute for Space Studies. Global warming is coming...

• The rate of warming is increasing. The 20th century's last two decades were the hottest in 400 years and possibly the warmest for several millennia, according to a number of climate studies. And the United Nations' Intergovernmental Panel on Climate Change (IPCC) reports that 11 of the past 12 years are among the dozen warmest since 1850. Global warming is coming...

• The Arctic is feeling the effects the most. Average temperatures in Alaska, western Canada, and eastern Russia have risen at twice the global average, according to the multinational Arctic Climate Impact Assessment report compiled between 2000 and 2004. Global warming is coming...

• Arctic ice is rapidly disappearing, and the region may have its first completely ice-free summer by 2040 or earlier. Polar bears and indigenous cultures are already suffering from the sea-ice loss. Global warming is coming...

• Glaciers and mountain snows are rapidly melting—for example, Montana's Glacier National Park now has only 27 glaciers, versus 150 in 1910. In the Northern Hemisphere, thaws also come a week earlier in spring and freezes begin a week later. Global warming is coming...

• Coral reefs, which are highly sensitive to small changes in water temperature, suffered the worst bleaching—or die-off in response to stress—ever recorded in 1998, with some areas seeing bleach rates of 70 percent. Experts expect these sorts of events to increase in frequency and intensity in the next 50 years as sea temperatures rise.

• An upsurge in the amount of extreme weather events, such as wildfires, heat waves, and strong tropical storms, is also attributed in part to climate change by some experts. Global warming is coming...

Penguin Decline Due to Global Warming?

The Earth is getting warmer, according to most scientists. In recent years that phenomenon has prompted researchers to investigate what effect rising temperatures are having on cold-loving penguins and other wildlife species. Global warming kills animals...
Les Underhill directs the Avian Demography Unit at the University of Cape Town in South Africa. He suspects that global climate change may be responsible for declining penguin populations on South Africa's Prince Edward Islands.

The islands dot the Indian Ocean some 1,000 miles (1,770 kilometers) off the South African coast. Global warming kills animals...

Most of the islands' penguin colonies are dwindling. According to Underhill, one reason for the decline may be a climate-induced southward shifting of food-rich waters. The change may have forced the seabirds to swim farther to forage.

Underhill and his colleagues will soon begin to test this idea. The researchers plan to place electronic tracking devices on the islands' penguins to record when they go out to sea to get food for their chicks and when they return. Global warming kills animals...

"We suspect that one of the consequences of global climate change is that, with warmer seas, the journeys will become longer," he said in an interview with the radio program Pulse of the Planet. Global warming kills animals...

Food-Rich Waters

The Prince Edward Islands sit near the southern boundary of the Antarctic Circumpolar Current (ACC). It is in these food-rich waters that the islands' penguins are thought to forage. Global warming kills animals...

Considered the greatest of all ocean currents, the Antarctic Circumpolar Current mixes waters from the Indian, Pacific, and Atlantic Oceans. It swirls about 140 million cubic meters (4.9 billion cubic feet) of water per second around Antarctica. Global warming kills animals...

The southern edge of the current is marked by a boundary separating it from the cold coastal waters along the Antarctic continental shelf. Waters to the north of the boundary are several degrees Celsius warmer than those to the south.

"The southern boundary of the ACC is noted for being a food source," said Eileen Hofmann, an oceanographer at Old Dominion University in Norfolk, Virginia. Global warming kills animals...

Melting glaciers signal global warming

For several years, evidence has been mounting that the global climate is steadily getting warmer. But whether the unusual weather patterns alarming environmentalists -- increasing temperatures, reduced snowfall, and rising sea levels -- are evidence of global warming or just passing blips in the earth's notoriously bumpy weather record continues to stir controversy. Global warming is coming... Before world leaders unanimously heed their cries of "wolf," scientists studying climate change must be able to tease apart regional climate changes and short-term weather fluctuations, such as El Niño, from permanent changes that are happening worldwide. Global warming is coming...

ASU geologist Rick Wessels is part of an international team of scientists studying the climate of the entire earth over several years with the Global Land Ice Measurement from Space (GLIMS) project. The team, led by United States Geological Survey (USGS) scientist Hugh Kieffer, is monitoring climate change by tracking the melting of glaciers across the earth. The global scale combined with a long study period will give the scientists the broad perspective needed to determine whether worldwide changes in climate are actually taking place. Global warming is coming...But in only seven months of monitoring, Wessels has already seen melting in glaciers all over Earth, which provides some solid evidence -- or liquid evidence -- for global warming.

At the Spring Meeting of the American Geophysical Union in Boston, May 29 to June 2, Wessels and co-author Jeff Kargel, a USGS geologist, will present the first round of results from this project in a talk titled "GLIMS: Documenting the Demise of the Earth's Glaciers using ASTER." Wessels will present evidence that thousands of glaciers are melting, corroborating similar arguments made by many other researchers over the last few years. Like shrinking ice cubes in an increasingly steamy atmospheric brew, glaciers around the world appear to be getting thinner or even disappearing entirely, says Wessels. The flooding caused by runoff from these melting glaciers could have disastrous consequences for people living nearby. Global warming is coming...

Using images of the earth taken from space, Wessels, along with over 50 other GLIMS researchers from 23 countries, is tracking changes in nearly all of the 160,000 glaciers around the world, only about 1,000 of which have been previously studied. Wessels's newest data come from NASA-operated ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer), which takes detailed color and infrared images of the entire earth.

Data collection using ASTER is still in the early stages, but by comparing the newest data with older records, Wessels and his colleagues have already noted some major changes in the sizes of many glaciers around the world. "The majority of these glaciers are receding," says Wessels.

Some growing and shrinking is normal for glaciers, and debris-rimmed lakes within some glaciers may come and go. Global warming is coming...Despite these fluctuations, glaciers usually maintain their size over the long term. But Wessels has seen a shift in the balance of this cycle. "At first glance, there's more shrinkage than growing," he says, "and there's now a trend for the lakes to stay and grow," rather than drying up or freezing over.

The newest images show that, in the Alps, where many years of records track the mountains' ice formations, several glaciers have disappeared in as little as 40 years. In Argentina, glaciers in the Patagonian ice fields have receded by an average of 1.5 kilometers over 13 years. And in the Himalayan mountains, glaciers are losing bulk as continued melting feeds lakes that sometimes run off to flood surrounding areas. Recently, a lake atop one Himalayan glacier threatened to overflow its natural dam within days, forcing local Nepalese engineers to quickly perform a controlled drain. Global warming is coming...

Because the melting and retreat is occurring at such a rapid pace, Wessels and his colleagues think global warming is the most likely explanation for the loss of glacial ice. "There is definitely a global climate change," Wessels asserts. Whether the climate warming is a natural cycle or caused by human activity, such as burning fossil fuels, is still being debated. Global warming is coming...