Myth: Global warming is just part of a natural cycle. The Arctic has warmed up in the past.
Fact: The global warming we are experiencing is not natural. People are causing it.

People are causing global warming by burning fossil fuels (like oil, coal and natural gas) and cutting down forests. Scientists have shown that these activities are pumping far more CO₂ into the atmosphere than was ever released in hundreds of thousands of years. This buildup of CO₂ is the biggest cause of global warming. Since 1895, scientists have known that CO₂ and other greenhouse gases trap heat and warm the earth. As the warming has intensified over the past three decades, scientific scrutiny has increased along with it. Scientists have considered and ruled out other, natural explanations such as sunlight, volcanic eruptions and cosmic rays. (IPCC 2001)

Though natural amounts of CO₂ have varied from 180 to 300 parts per million (ppm), today's CO₂ levels are around 380 ppm. That's 25% more than the highest natural levels over the past 650,000 years. Increased CO₂ levels have contributed to periods of higher average temperatures throughout that long record. (Boden, Carbon Dioxide Information Analysis Center)

As for previous Arctic warming, it is true that there were stretches of warm periods over the Arctic earlier in the 20th century. The limited records available for that time period indicate that the warmth did not affect as many areas or persist from year to year as much as the current warmth. But that episode, however warm it was, is not relevant to the issue at hand. Why? For one, a brief regional trend does not discount a longer global phenomenon.

We know that the planet has been warming over the past several decades and Arctic ice has been melting persistently. And unlike the earlier periods of Arctic warmth, there is no expectation that the current upward trend in Arctic temperatures will reverse; the rising concentrations of greenhouse gases will prevent that from happening.

Myth: We can adapt to climate change — civilization has survived droughts and temperature shifts before.
Fact: Although humans as a whole have survived the vagaries of drought, stretches of warmth and cold and more, entire societies have collapsed from dramatic climatic shifts.

The current warming of our climate will bring major hardships and economic dislocations — untold human suffering, especially for our children and grandchildren. We are already seeing significant costs from today's global warming which is caused by greenhouse gas pollution. Climate has changed in the past and human societies have survived, but today six billion people depend on interconnected ecosystems and complex technological infrastructure.

What's more, unless we limit the amount of heat-trapping gases we are putting into the atmosphere, we will face a warming trend unseen since human civilization began 10,000 years ago. (IPCC 2001)

The consequences of continued warming at current rates are likely to be dire. Many densely populated areas, such as low-lying coastal regions, are highly vulnerable to climate shifts. A middle-of-the-range projection is that the homes of 13 to 88 million people around the world would be flooded by the sea each year in the 2080s. Poorer countries and small island nations will have the hardest time adapting. (McLean et al. 2001)

In what appears to be the first forced move resulting from climate change, 100 residents of Tegua island in the Pacific Ocean were evacuated by the government because rising sea levels were flooding their island. Some 2,000 other islanders plan a similar move to escape rising waters. In the United States, the village of Shishmaref in Alaska, which has been inhabited for 400 years, is collapsing from melting permafrost. Relocation plans are in the works.

Scarcity of water and food could lead to major conflicts with broad ripple effects throughout the globe. Even if people find a way to adapt, the wildlife and plants on which we depend may be unable to adapt to rapid climate change. While the world itself will not end, the world as we know it may disappear.

Myth: Recent cold winters and cool summers don't feel like global warming to me.
Fact: While different pockets of the country have experienced some cold winters here and there, the overall trend is warmer winters.

Measurements show that over the last century the Earth's climate has warmed overall, in all seasons, and in most regions. Climate skeptics mislead the public when they claim that the winter of 2003 - 2004 was the coldest ever in the northeastern United States. That winter was only the 33rd coldest in the region since records began in 1896. Furthermore, a single year of cold weather in one region of the globe is not an indication of a trend in the global climate, which refers to a long-term average over the entire planet.

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