Have you ever been in a situation where you're talking with friends and the conversation turns to global warming? It's hard to be an expert. Sometimes it's hard to even show the slightest bit of concern without being met with with skepticism.
Compiled here are some of the most commonly heard myths explained.
"The current warming cycle is natural; the earth has been warming and cooling for millions of years."
What we are experiencing today is not natural. It's true the earth goes through long cycles of warm and cold periods due to small variations in the planet's tilt and rotation. But science tells us the climate change we are experiencing does not fit the planetary cycle. We are beyond anything the planetary cycle would account for.
"A temperature rise of 1 degree is inconsequential, and the predicted rise of 2-3 degrees is barely anything."
Actually 1 degree C (1.7 F) of average temperature increase already is causing sea level to rise and ecosystems to shift. And, temperatures are rising faster at the poles, with more severe consequences such as the rapid melting of polar ice caps. A degree or two more will only make these impacts worse.
"Humans are only responsible for a small amount of the carbon dioxide that goes into the atmosphere each year, so the warming must be natural."
Human activity is releasing carbon that has been trapped in the ground for millions of years and is upsetting the balance of the Carbon Cycle. Unlike when the Pilgrims landed at Plymouth Rock, today people annually release 7 gigatons of CO2, largely a result of burning fossil fuels, which has increased the CO2 in the atmosphere by 37% in 200 years.
"The warming we have seen is due mostly to the sun."
For the last 30 years, while the earth's temperature has been rapidly rising, the sun has shown no trend of increased solar radiation. There simply isn't any reliable study showing the sun's intensity has increased, causing the climate to warm.
"We cannot even accurately predict the weather a week from now, how can we believe we can predict what will happen 50 years from today?"
”Weather" and "climate" are very different terms. A weather prediction is a short term outlook of an hour, a day or perhaps a week. Predicting weather is often challenging because temperature, precipitation and other factors are constantly changing. Analysis of the climate, however, involves studying weather patterns over months, seasons, decades, or even centuries. Long-term climate analysis helps determine activities such as what crops to plant for a given region and when to harvest them. Future climate projections are based on historical data.
"Scientists only have 145 years of temperature data; this is not enough long enough to draw accurate conclusions."
More information on past conditions exists than modern human measurements. Humans have been tracking direct temperature measurements for the last 145 years with the use of thermometers and satellites. Scientists are also able to measure past temperatures going back many thousands of years with a high degree of accuracy from ice core and ocean floor samples.
"Ice is building up in central Antarctica, so global warming is not happening."
Ice is building up in central Antarctica, but being lost on the edges and being lost very rapidly in Greenland. The loss of ice from Greenland has doubled in the past 10 years, and Antarctic glaciers have been retreating over the past half century. There are some reports of "Antarctic cooling," but cooling in one region does not change the fact that globally, temperatures are rising.
"In the 1970s scientists were predicting a coming ice age. Now they turn around and say the globe is warming."
Unfortunately, this myth is a product of the popular press in the 1970s misinterpreting scientific findings. There was no widespread belief among scientists at the time that we were entering a period of cooling.
"During the 1940s and 1950s the earth's temperature went down, even while CO2 rose. Therefore, CO2 is not connected to global warming."
The scientific community now understands that air pollution (dust, smoke, chemicals) was masking the impact of increased greenhouse gases. Also, the amount of increased CO2 was much less as recently as three or four decades ago.
"The U.S. is actually a net sink (or absorber) of CO2."
The U.S. emits one-third of all CO2 today. A small amount is absorbed by soil annually, but it does not offset the release from burning fossil fuels.
"The 'hockey stick' graph, which is the basis for the claim of global warming, is proven to be flawed."
Scientists have used thousands of independent pieces of evidence gathered over decades to determine that global warming is primarily a result of human activities. So it is wholly false to argue that one graph is the basis for global warming. The "hockey stick" controversy is a complicated issue revolving around statistics and modeling techniques.
Download the Myth Buster Fact Sheet (pdf)
Sem comentários:
Enviar um comentário