Topic: Global Warming

[Firestarter]

This is some fast facts on the national geographic site, not totally human caused but us burning fuel and so forth does aggravate it:

Global Warming Fast Facts
National Geographic News
Updated June 14, 2007

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.



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.

• 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.

• 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.

• 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.

• 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.

• 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.

Are Humans Causing It?

• "Very likely," the IPCC said in a February 2007 report.

The report, based on the work of some 2,500 scientists in more than 130 countries, concluded that humans have caused all or most of the current planetary warming. Human-caused global warming is often called anthropogenic climate change.




• Industrialization, deforestation, and pollution have greatly increased atmospheric concentrations of water vapor, carbon dioxide, methane, and nitrous oxide, all greenhouse gases that help trap heat near Earth's surface. (See an interactive feature on how global warming works.)

• Humans are pouring carbon dioxide into the atmosphere much faster than plants and oceans can absorb it.

• These gases persist in the atmosphere for years, meaning that even if such emissions were eliminated today, it would not immediately stop global warming.

• Some experts point out that natural cycles in Earth's orbit can alter the planet's exposure to sunlight, which may explain the current trend. Earth has indeed experienced warming and cooling cycles roughly every hundred thousand years due to these orbital shifts, but such changes have occurred over the span of several centuries. Today's changes have taken place over the past hundred years or less.

• Other recent research has suggested that the effects of variations in the sun's output are "negligible" as a factor in warming, but other, more complicated solar mechanisms could possibly play a role.

What's Going to Happen?

A follow-up report by the IPCC released in April 2007 warned that global warming could lead to large-scale food and water shortages and have catastrophic effects on wildlife.

• Sea level could rise between 7 and 23 inches (18 to 59 centimeters) by century's end, the IPCC's February 2007 report projects. Rises of just 4 inches (10 centimeters) could flood many South Seas islands and swamp large parts of Southeast Asia.

• Some hundred million people live within 3 feet (1 meter) of mean sea level, and much of the world's population is concentrated in vulnerable coastal cities. In the U.S., Louisiana and Florida are especially at risk.

• Glaciers around the world could melt, causing sea levels to rise while creating water shortages in regions dependent on runoff for fresh water.

• Strong hurricanes, droughts, heat waves, wildfires, and other natural disasters may become commonplace in many parts of the world. The growth of deserts may also cause food shortages in many places.

• More than a million species face extinction from disappearing habitat, changing ecosystems, and acidifying oceans.

• The ocean's circulation system, known as the ocean conveyor belt, could be permanently altered, causing a mini-ice age in Western Europe and other rapid changes.

• At some point in the future, warming could become uncontrollable by creating a so-called positive feedback effect. Rising temperatures could release additional greenhouse gases by unlocking methane in permafrost and undersea deposits, freeing carbon trapped in sea ice, and causing increased evaporation of water.

[Firestarter]

Also from Nat. Geo.

By 2050 Warming to Doom Million Species, Study Says
John Roach
for National Geographic News
Updated July 12, 2004

By 2050, rising temperatures exacerbated by human-induced belches of carbon dioxide and other greenhouse gases could send more than a million of Earth's land-dwelling plants and animals down the road to extinction, according to a recent study.

"Climate change now represents at least as great a threat to the number of species surviving on Earth as habitat-destruction and modification," said Chris Thomas, a conservation biologist at the University of Leeds in the United Kingdom.

Thomas is the lead author of the study published earlier this year in the science journal Nature. His co-authors included 18 scientists from around the world, making this the largest collaboration of its type.

Townsend Peterson, an evolutionary biologist at the University of Kansas in Lawrence and one of the study's co-authors, said the paper allows scientists for the first time to "get a grip" on the impact of climate change as far as natural systems are concerned.

"A lot of us are in this to start to get a handle on what we are talking about," he said. "When we talk about the difference between half a percent and one percent of carbon dioxide emissions what does that mean?"

The researchers worked independently in six biodiversity-rich regions around the world, from Australia to South Africa, plugging field data on species distribution and regional climate into computer models that simulated the ways species' ranges are expected to move in response to temperature and climate changes.

"We later met and decided to pool results to produce a more globally relevant look at the issue," said Lee Hannah, a climate change biologist with Conservation International's Center for Applied Biodiversity Science in Washington, D.C.

Study Results

According to the researchers' collective results, the predicted range of climate change by 2050 will place 15 to 35 percent of the 1,103 species studied at risk of extinction. The numbers are expected to hold up when extrapolated globally, potentially dooming more than a million species.

"These are first-pass estimates, but they put the problem in the right ballpark … I expect more detailed studies to refine these numbers and to add data for additional regions, but not to change the general import of these findings," said Hannah.

Writing in an accompanying commentary to the study in Nature, J. Alan Pounds of the Monteverde Cloud Forest Reserve in Costa Rica, and Robert Puschendorf, a biologist at the University of Costa Rica, say these estimates "might be optimistic."

As global warming interacts with other factors such as habitat-destruction, invasive species, and the build up of carbon dioxide in the landscape, the risk of extinction increases even further, they say.

By 2050 Warming to Doom Million Species, Study Says
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In agreement with the study authors, Pounds and Puschendorf say taking immediate steps to reduce greenhouse gas emissions is imperative to constrain global warming to the minimum predicted levels and thus prevent many of the extinctions from occurring.

"The threat to life on Earth is not just a problem for the future. It is part of the here and now," they write.

Climate Scenarios

The researchers based their study on minimum, mid-range, and maximum future climate scenarios based on information released by the United Nation's Intergovernmental Panel on Climate Change (IPCC) in 2001.

According to the IPCC, temperatures are expected to rise from somewhere between 1.5 and more than 4 degrees Fahrenheit (0.8 and more than 2 degrees Celsius) by the year 2050.

"Few climate scientists around the world think that 2050 temperatures will fall outside those bounds," said Thomas. "In some respects, we have been conservative because almost all future climate projections expect more warming and hence more extinction between 2050 and 2100."

In addition, the researchers accounted for the ability of species to disperse or successfully move to a new area, thus preventing climate change-induced extinction. They used two alternatives: one where species couldn't move at all, the other assuming unlimited abilities for movement.

"We are trying to bracket the truth," said Peterson. "If you bracket the truth and look at the two endpoints and they give the same general message, then you can start to believe it."

Outside of the small group of researchers working directly on the impacts of climate change to species diversity, "the numbers will come as a huge shock," said Thomas.

Extinction Prevention

The researchers point out that there is a significant gap between the low and high ends of the species predicted to be on the road to extinction by 2050. Taking action to ensure the climate ends up on the low end of the range is vital to prevent catastrophic extinctions.

"We need to start thinking about the fullest of costs involved with our activities, the real costs of what we do in modern society," said Peterson.

Thomas said that since there may be a large time lag between the climate changing and the last individual of a doomed species dying off, rapid reductions of greenhouse gas emissions may allow some of these species to hang on.

"The only conservation action that really makes sense, at a global scale, is for the international community to minimize warming through reduced emissions and the potential establishment of carbon-sequestration programs," he said.