6 Major Climate Change Myths, Debunked

פורסם: 8 ביולי 2014, 12:15 על ידי: Sustainability Org   [ עודכן 8 ביולי 2014, 12:16 ]

When it comes to climate change, there are many misconceptions, distortions, outright lies and memes circulating online. In fact, entire websites argue the mainstream scientific conclusion that manmade emissions of greenhouse gases are causing harmful global warming. Don't forget the sites designed to counter those sites, and on and on.

In an effort to clear up some of the climate confusion, here are the top six climate myths, debunked.

1. Myth: The earth can't be getting hotter, because it's cold out.

Truth: There's a difference between short-term weather variability and long-term climate change.

Weather is the day-to-day variations in precipitation, temperature and clouds. Climate, on the other hand, is the average weather pattern in a place over many years. When examining climate change, scientists typically look at 30-year timeframes or longer, whereas weather involves a 5-10-day forecasts.

An old adage says, "Climate is what you expect. Weather is what you get." Or, as Stephen Colbert once said, "Isn't climate just made up of thousands of little weathers?"

Temperature Change

Global land and ocean temperatures showing the long-term increase associated with global warming, and the year-to-year variability that is part of the trend.

Image: NASA

The National Climate Assessment states:

While there is a clear long-term global warming trend, some years do not show a temperature increase relative to the previous year, and some years show greater changes than others. These year-to-year fluctuations in temperature are due to natural processes, such as the effects of El Niños, La Niñas, and volcanic eruptions.

So, even as the climate warms, there will still be cold days and snowstorms.

In fact, some scientists think that by melting Arctic sea ice, global warming may be causing bigger swings in the jet stream that can encourage frigid air to move south into the winter, into parts of the U.S. and Europe.

2. Myth: The climate has changed before, so this change must be normal, too.

Yes, the climate has changed, sometimes extremely rapidly, in the past.

Truth: Natural factors turned the climate dial in the past, but now, humans are causing the bulk of the change.

One of the biggest control knobs of the climate system (both in history and now) is carbon dioxide, or CO2.

Truth: Right now, the amount of CO2 in the atmosphere is the highest it's been in all of human history.

Temperatures and CO2

Global annual average temperature has increased by more than 1.5 degrees Fahrenheit. The black line shows atmospheric carbon dioxide (CO2) concentration in parts per million (ppm).

Image: National Climate Assessment

3. Myth: The Sun is responsible for global warming.

Solar activity can cause climate swings.

Truth: Scientists have conducted studies of the sun's interaction with the climate and concluded that none of its recent behavior accounts for today's shift.

Solar Cycles and Surface Temperatures

Changes in the global surface temperature (top) and the solar flux (bottom) since 1900 (temperatures are relative to 1961-1990; solar flux is relative to the total average irradiance from the sun of about 1360 watts per square meter).

Image: National Climate Assessment

The majority of the warming at the global scale over the past 50 years can only be explained by the effects of human influences, especially the emissions from burning fossil fuels and from deforestation, while natural factors have played a more minor role.

4. Myth: Climate change is actually good for us.

NASA Blue Marble

Nasa "Blue Marble" image taken in January 2012 of the Earth aken from the VIIRS instrument aboard NASA's Suomi NPP satellite.

Image: NASA

Climate change may mean longer growing seasons and newly accessible territory for some countries, such as Russia and Canada.

Truth: Overall, the negatives, such as flooding and drought, outweigh the positives. This is especially true if emissions aren't reduced and temperatures increase at a rapid pace.

For example, a recent report found that climate change could cost the U.S. economy hundreds of billions of dollars within the next few decades.

5. Myth: CO2 can't be dangerous, because plants need it.

Plants do need CO2 to grow.

But research has shown that with too much CO2 in the air, plants may actually suffer and crops may become less nutritious.

Truth: Extreme heat and precipitation extremes can hurt crop yields.

6. Myth: Scientists don't agree about climate change.

Truth: Climate scientists are in near 100% agreement that human activities are contributing to global warming.

Sea level rise projections

Range of projected sea level rise depending on greenhouse gas emissions during the 21st century.

Image: U.N. IPCC

The main areas of uncertainty concern how significant the warming will be, and how different places will be affected.

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Topics: Climate, debunked, Mashable Must Reads, myths, US & World, Video
Image: NASA Goddard Institute for Space Studies

Source: mashable.com