Myth #1: The science of global warming is uncertain, and not all scientists believe in it.

Fact: There is no debate among scientists about the basic facts of global warming.

While not all scientists may agree that humans are causing global warming, according to the Environmental Defense Fund, “the most respected scientific bodies have stated unequivocally that global warming is occurring, and people are causing it by burning fossil fuels and cutting down forests.”

In 2005, the U.S. National Academy of Sciences issued a joint statement with 10 other National Academies of Science saying, "the scientific understanding of climate change is now sufficiently clear to justify nations taking prompt action. It is vital that all nations identify cost-effective steps that they can take now, to contribute to substantial and long-term reduction in net global greenhouse gas emission.”

Myth #2: Global warming will be beneficial. Higher levels of carbon dioxide will increase crop growth and reduce cold-related deaths.

Fact: Global warming has serious consequences that will far outweight any benefits.

Although carbon dioxide can stimulate plant growth in certain circumstances, scientists say this “CO2 fertilization effect,” will diminish as plants adapt to changes in the environment. Plus, extra carbon dioxide may benefit undesirable plant species, such as weeds, more than crops.

Also, increasing carbon dioxide levels cause ocean acidification, which can have adverse impacts on marine organisms. In fact, the oceans have already absorbed about 50 percent of the carbon dioxide released from the burning of fossil fuels.

While warmer weather may sound good for people and animals, a warming climate can actually have devastating effects. Melting glaciers and rising seas would flood coastal towns and contaminate water supplies. Plus, global warming contributes to extreme weather events like droughts, floods and heat waves, which could be deadly.

Myth #3: Recent cold winters and snowstorms indicate that global warming isn't occurring.

Fact: Different parts of the world may experience snow or cold weather, but the global trend is warmer winters.

A year of cold weather in one region isn’t evidence of a trend in the global climate. Measurements reveal that the Earth’s climate has warmed overall, in most regions, during the last century, according to the U.S. National Academy of Sciences.

Myth #4: People aren't causing global warming — it's part of a natural cycle.

Fact: The global warming the Earth is experiencing isn't natural.

Scientists have proved that deforestation and the burning of fossil fuels are releasing more carbon dioxide into the air, which is the main cause of global warming. Since 1985, scientists have known that greenhouse gases like carbon dioxide trap heat, and scientific study has already ruled out natural explanations like volcanic eruptions and sunlight.

Although carbon dioxide is naturally found on Earth, these ordinary amounts typically vary from 180 to 300 parts per million, but today’s levels are around 380 ppm, according to the Environmental Defense Fund. That's 25 percent more than the highest natural levels of carbon dioxide over the past 650,000 years.

MNN homepage photo: Gewitterkind/iStockphoto

Laura Moss writes about a variety of topics with a focus on animals, science, language and culture. But she mostly writes about cats.

Global warming myths
Global warming myths. There are many myths circulating about global warming. Here are the facts.