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It's not a demon thing
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excerpts from Global Warming Fast Facts
By Brian Handwerk for National Geographic News
There is little doubt that the planet is warming. Over the last century the average temperature has climbed about 1 degree Fahrenheit (0.6 of a degree Celsius) around the world.
There is more warming at higher latitudes. The multinational Arctic Climate Impact Assessment (ACIA) report recently concluded that in Alaska, western Canada, and eastern Russia, average temperatures have increased as much as 4 to 7 degrees Fahrenheit (3 to 4 degrees Celsius) in the past 50 years. The rise is nearly twice the global average. In Barrow, Alaska (the U.S.'s northernmost city) average temperatures are up over 4 degrees Fahrenheit (2.5 to 3 degrees Celsius) in 30 years
There is more warming at higher latitudes. The multinational Arctic Climate Impact Assessment (ACIA) report recently concluded that in Alaska, western Canada, and eastern Russia, average temperatures have increased as much as 4 to 7 degrees Fahrenheit (3 to 4 degrees Celsius) in the past 50 years. The rise is nearly twice the global average. In Barrow, Alaska (the U.S.'s northernmost city) average temperatures are up over 4 degrees Fahrenheit (2.5 to 3 degrees Celsius) in 30 years.
Data from the distant past show rapid climate change is possible.Over the last million years the Earth has fluctuated between colder and warmer periods. The shifts have occurred in roughly 100,000-year intervals thought to be regulated by sunlight. Earth's sunlight quota depends upon its orbit and celestial orientation
Arctic ice is at risk. Rising temperatures have a dramatic impact on Arctic ice, which serves as a kind of "air conditioner" at the top of the world. Since 1978 Arctic sea ice area has shrunk by some 9 percent per decade, and thinned as well.
The Arctic impacts affect people and animals. In the Arctic the impacts of a warming climate are being felt already. Coastal Indigenous communities report shorter periods of sea ice, which fails to temper ocean storms and their destructive coastal erosion. Increased snow and ice melt have caused higher rivers while thawing permafrost has wreaked havoc with roads and other infrastructure. Some communities have had to move from historic coastline locations.
Glaciers are shrinking. Vast quantities of fresh water are tied up in the world's many melting glaciers. When Montana's Glacier National Park was created in 1910 it held some 150 glaciers. Now fewer than 30, greatly shrunken glaciers, remain. Tropical glaciers are in even more trouble. The legendary snows of Tanzania's Mount Kilimanjaro 19,340-foot (5,895-meter) peak have melted by some 80 percent since 1912 and could be gone by 2020.
Sea levels have risen and fallen many times over the Earth's long geological history. Average global sea level has risen by 4 to 8 inches (10 to 20 cm) over the past century according to the IPCC.
Warming could alter the ocean conveyor belt. The ocean's circulation system, known as the ocean conveyor belt, moderates global temperatures by moving tropical heat around the planet. Global warming could alter the balance of this system, via an influx of freshwater from melting ice caps for example, creating unforeseen and possibly fast-paced change.
Extreme weather could become common. Climate models suggest that globalwarming could cause more frequent extreme weather conditions. Intense hurricanes and storm surges could threaten coastal communities, while heat waves, fires and drought could also become more common.
Human activities have contributed to global warming. Since the 1860s, increased industrialization and shrinking forests have helped raise the atmosphere's CO2 level by almost 100 parts per million -- and Northern Hemisphere temperatures have followed suit. Increases in temperatures and greenhouse gasses have been even sharper since the 1950s.
Global warming affects plants, birds and amphibians also. Studies show that many European plants now flower a week earlier than they did in the 1950s and also lose their leaves 5 days later.
Warming could cause plant and animal extinction. 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.
Coral reefs are also affected. Coral reefs worldwide are "bleaching," losing key algae and resident organisms, as water temperatures rise above 85 degrees Fahrenheit (29.5 degrees Celsius) through periods of calm, sunny weather. Scientists worry that rapid climate change could inhibit the ability of many species to adapt within complex and interdependent ecosystems.
Positive effects are possible. The effects of a warming globe may not be entirely negative. Heating costs could decline for those in colder climates, while vast marginal agricultural areas in northern latitudes might become more viable. Arctic shipping and resource extraction operations could also benefit—summer sea ice breakup in Hudson Bay already occurs two to three weeks earlier than it did half a century ago.
But many species could be hit hard—including humans. The most vulnerable are peoples living in the far North, those perched along the world's coasts, and millions dependent on subsistence agriculture subject to the vagaries of a changing climate
