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Five Myths About Extreme Weather

This story originally appeared in the Washington Post.

It's too darn hot. From Maine to Hawaii, the mercury has been rising relentlessly. The oven-like conditions in the United States are just the latest in a series of extreme weather events over the past year -- epic floods in Pakistan and Australia, record heat waves in Moscow, the heaviest snowfall in more than a century in South Korea. These extremes are pushing the limits of human experience. What is driving this phenomenon? And rather than just complain, what can we do about it?

1. This summer is much hotter than normal

It feels hot for a reason, and not just in the United States. Last month's global average land surface temperature was the fourth warmest on record. And July is doing its best to outdo June. According to the National Oceanic and Atmospheric Administration, 49 states---all except Delaware---have had record highs in the past three weeks. In Washington, a heat wave sweeping the East Coast is pushing temperatures into the triple digits.

However, while suffering Washingtonians might be forgiven for regarding this summer as an aberration, they would be wrong. Globally, June was the 316th month in a row that had a higher temperature than the 20th century average. So, while it is indeed much hotter than it used to be, we may be witnessing a new normal in heat and other extreme weather. This month's temperature records may not stand for long.

2. "Hundred year" weather events happen only once every 100 years.

Hundred-year weather events no longer live up to their name. In 2005, for instance, a devastating "once a century" drought hit the Amazon, only to be followed by another in 2010. Globally, previously rare weather events have been occurring with startling frequency. Consider the massive floods that inundated a fifth of Pakistan last year, and submerged eastern Australia, and America's heartlands this year. It's time for meteorologists to come up with a new, more accurate term.

Of course, what scientists actually mean by "one in 100 years" is not that a major flood, drought or hurricane will strike a given place only once a century, but rather that there is a 1 percent chance of such an event in any given year. Either way, the fact that what were once considered hundred-year events seem to be happening more often is consistent with climate models projecting that rising global average temperatures will lead to more frequent and severe extreme weather.

3. Extreme droughts and extreme floods can't both be due to climate change

It seems counter-intuitive that climate change could cause both withering droughts and devastating floods. Yet it does. Scientists have found that climate change can trigger periods of intense and heavy rainfall that can be followed by long periods of dry weather, marked by little precipitation. This combination of severe rainstorms and droughts can, in turn, lead to more flooding, landslides, soil erosion, and associated disasters. There are signs in some places that this may already be underway.

For example, from 1951 to 2000, heavy monsoons in India became more frequent and intense, while more moderate rains happened less often. Similarly, in China, severe droughts this spring were followed by massive flooding, which has killed nearly 200 people and caused more than 1.5 million to be evacuated.

4. An extra one or two degrees in temperature is no big deal

When it's already 100 degrees outside, one degree more doesn't seem like much. But in terms of the global average, a one-degree temperature rise has huge implications for people and the planet.

Since pre-industrial times, the global average surface temperature has increased by 1.4 degrees Fahrenheit---with more than one degree of that warming happening in the past three decades. And we are already witnessing significant changes. In many parts of the world, cold days and nights have become rarer, and hot days and nights more common, over the past half-century. Arctic sea ice, Greenland's ice sheet, and glaciers in the Alps and the Antarctic Peninsula are all melting faster. The oceans have become more acidic as a result of the buildup of greenhouse gases, and the warming of rivers and lakes is affecting freshwater fish and other species. As are result, animals and plants are migrating toward poles or higher elevations in search of more hospitable habitats.

And all this is happening with just 1.4 degrees of warming. What's more, this is just an average, with actual temperatures rising at different rates, and with varying impacts, around the world. Without action to reduce carbon emissions, many leading climate scientists are projecting that the planet's average temperature could rise as much as 11.5 degrees by the end of the century. The consequences are hard to imagine.

5. Everyone complains about the weather, but no one does anything about it

We all love to complain about the weather. But the old saying is not quite accurate. There is, in fact, a lot that governments, businesses and people around the world can do---and are already doing---to cut back on heat-trapping gases and prepare for extreme weather.

At least 85 nations have pledged to reduce greenhouse gas emissions or limit their growth by 2020 by shifting to renewable energy, increasing energy efficiency and protecting forests, among other efforts. Similarly, some Fortune 500 companies and even the U.S. military are working to reduce their carbon emissions. A good start, but not nearly enough.

Many countries, cities and communities are preparing for the impact of rising global temperatures. In Bangladesh, for example, the government's actions to improve disaster preparedness have helped reduce death tolls from cyclones. Cyclone Sidr in 2007 claimed 3,400 lives, whereas a similar cyclone in 1991 led to roughly 140,000 deaths. And Vietnam has invested in mangrove restoration to rebuild a natural barrier to protect coastlines from flooding. The World Resources Report 2010-2011, produced by the World Resources Institute, the United Nations Development Program, the United Nations Environment Program and the World Bank, highlights how governments are planning for climate change and extreme weather.

But we can do much more to reduce the carbon emissions that contribute to the problem in the first place. When it comes to our warming planet, it's time for less hot air and more action.

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