Rabu, 25 Mei 2011

Global Warming — Fact or Myth?

Global Warming — Fact or Myth?
6 common misunderstandings about global warming. Or is that climate change?

Myth or fact? There are a lot of misconceptions about global warming that have cropped up in recent months. Here's a look at some of them:


Fact or Myth? "Snowmageddon" and all those other weird U.S. snowstorms this winter prove that global warming isn't real.




Myth
The reaction to "Snowmageddon" is an example of a common misunderstanding about climate change. Weather events are not climate; climate is the accumulation of weather events over an extended period of time. So a cold summer day doesn't prove global warming is false any more than a heat wave in winter proves it's true. That said, the effects scientists predict from global warming are sometimes counterintuitive. While snow is associated with winter, warmer winter temperatures can result in more snow, since warmer air can hold more moisture. One of the most well-documented predictions about global warming is that it will result in more intense storms, in any season, but may leave longer droughts between those storms.

Fact or Myth? The U.N. scientific report on global warming was full of errors and should not be trusted.

Myth
There have been errors discovered in the U.N.'s landmark report on climate science. The errors concern facets of climate change, like how fast Himalayan glaciers have melted, or how fast sea levels will rise in the Netherlands. The errors are a black eye for an organization that won a Nobel Peace Prize for the authoritative work it has done on the subject. However, these errors amount to t's left uncrossed and i's left undotted. The sentences still read loud and clear about the overall consensus about fundamental issues: That the Earth is warming, that our pollution is a primary cause, and that continued warming would have consequences worldwide, many of them costly to human life and property, and to wildlife.

Fact or Myth? There has been no global warming in the past 10 or 15 years.

Myth
The hottest year ever recorded was in 1998, according to measurements by the British University of East Anglia, or 2005 (with 1998 ranking very close) according to measurements by NASA. Both agree that the first decade of the 21st century was the hottest ever recorded, which means the hottest since the 1880s. Comparing the temperature to other data hidden in the natural world, like tree rings or layers of Arctic ice, scientists can determine that we're likely experiencing temperatures higher than any time in thousands of years.

"Climate change" is a more accurate description for what's happening than "global warming."
Fact
While it is true that the world as a whole is warming, "climate change" is more accurate, particularly when it comes to how individuals in different regions will experience these changes. Global warming is the driving force, but climate change is what we will experience. What will climate change look like? It could mean more intense storms or more prolonged droughts. It could mean more risk of wildfires in one area, and more flooded basements in another. It could make one farmer's field more productive, while killing that of another. Some even have called the effects of climate change "global weirding." In general, scientists expect climate change will affect different regions very differently.

Fact or Myth? Carbon dioxide is natural. Breathing is not pollution.

Myth
There's nothing wrong with breathing, of course, and nothing unnatural about carbon dioxide. Breathing is not causing the world any harm. So if carbon dioxide exhaled in our breath is harmless, how can carbon dioxide "exhaled" by power plants, tailpipes and factories be a problem? A clue lies in the name we have for what we burn: fossil fuels. By burning coal, oil and gas, we take carbon that had been buried deep underground for millions of years, and we transfer it to the atmosphere. There, it acts as a chemical greenhouse, trapping more of the sun's heat close to the Earth's surface. There's about 40% more carbon in the atmosphere today than there was in pre-industrial times. In fact, the concentration of carbon dioxide in the atmosphere is higher today than at any point in the last 650,000 years, before humans walked the Earth -- before even Neanderthals walked the Earth. Natural processes also have an effect on the concentration of carbon dioxide and other greenhouse gases (those early human-like species weren't driving SUVs), and other factors affect the climate beyond the makeup of chemicals in the atmosphere, but scientists studying the causes of global warming agree that human pollution is a driving force for the climate change we've documented in recent decades.

Fact or Myth? Even if we stopped driving cars completely today, the climate would not be affected.

Fact
Carbon dioxide, which is released from burning fossil fuels like coal, oil and gas, survives for years or decades. When you hear news reports stating that other gasses are "more potent" than carbon dioxide, it's often because they last even longer in the atmosphere than carbon dioxide, trapping heat all the while. The fact is, the pollution we've emitted in the past will stay with us for some time. So why act now? We understand today that future generations will have to deal with planetary changes we're setting in motion. Past generations didn't have the knowledge we do.

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