From PTT的《TY_Research》(大氣科學板)
The 10 most common misconceptions about Global Warming
Misconception 1
” Scientists disagree about whether humans are causing the Earth’s climate to change.”
→ In fact, there is strong scientific consensus that human activities are changing the Earth’s climates. Scientists overwhelmingly agree that the Earth is getting warmer, that this trend is caused by people, and that if we continue to pump greenhouse gases into the atmosphere, the warming will be increasingly harmful.
Misconception 2
” Lots of things can impact climate — so there’s no reason we should single out CO2 to worry about.”
→ Climate is sensitive to many things besides carbon dioxide — sunspots, for one, as well as water vapor. But this just proves how much we should worry about CO2 and other human-influenced green house gases. The fact that the climate system has been shown to be sensitive to many sorts of natural changes throughout history should serve as a red flag: We need to pay attention to the massive and unprecedented changes we’re causing. We have become more powerful than any force of nature.
Misconception 3
” Climate naturally varies over time, so any change we’re seeing now is just part of a natural cycle.”
→ Climate does naturally change. By studying tree rings, take sediments, ice cores, and other natural features that provide a record of past climates, scientists know that changes in climate, including abrupt changes, have occurred throughout history. But these changes all took place with natural variations in carbon dioxide levels that were smaller than the ones we are now causing. Cores taken from deep in the ice of Antarctica show that carbon dioxide levels are higher now than they have been at any time in the last 650,000 years, which means we are outside the realm of natural climate variation. More CO2 in the atmosphere means warming temperatures.
Misconception 4
” The hole in the ozone layer causes global warming.”
→ There is a relationship between climate change and the ozone hole, but this isn’t it. The hole in the ozone layer — a part of the upper atmosphere that contains high concentrations of ozone gas and shields the planet from the sun’s radiation — is due to man-made chemicals called CFCs, which were banned by an international agreement called the Montreal Protocol. The hole causes extra UV radiation to reach the Earth’s surface, but it does not affect the Earth’s temperature. The only connection between the ozone layer and climate change is almost the exact opposite of the myth stated above. Global warming — while not responsible for the ozone hole — could actually slow the natural repairing of the ozone layer. Global warming heats the lower atmosphere but actually cools the stratosphere, which can worsen stratospheric ozone loss.
Misconception 5
” There is nothing we can do about climate change. It’s already too late.”
→ This is the worst misconception of all. If “denial ain’t just a river in Egypt,” despair ain’t just a tire in the trunk. There are lots of things we can do — but we need to start now. We can’t ignore the causes and impacts of climate change any longer. We need to reduce our use of fossil fuels, through a combination of government initiatives, industry innovation, and individual action. Dozens of things you can do are outlined in this resource guide.
Misconception 6
” Antarctica’s ice sheets are growing, so it must not be true that global warming is causing glaciers and sea ice to melt.”
→ Some ice on Antarctica may be growing — though other areas of the continent are clearly melting and a new 2006 study shows that overall the ice is shrinking in Antarctica. Even if some of the ice is getting bigger, not shrinking, this doesn’t change the fact that global warming is causing glaciers and sea ice to melt around the world. Globally, more than 85% of glaciers are shrinking. And in any case, localized impacts of climate change don’t cancel out the global trends that scientists are observing. Some people also mistakenly claim (in Michael Crichton’s novel State of Fear, for instance) that Greenland’s ice is growing. In fact, recent satellite data from NASA shows that Greenland’s ice cap is shrinking every year, causing sea levels to rise. The loss of that ice doubled from 1996 to 2005. Greenland lost 50 cubic kilometers of ice in 2005 alone.
Misconception 7
” Global warming is a good thing, because it will rid us of frigid winters and make plants grow more quickly.”
→ This myth just doesn’t seem to die. Because local impacts will vary, it’s true that some specific places may experience more pleasant winter weather. But the negative impact of climate change vastly outweighs any local benefits. Take the oceans, for example. Changes to the oceans caused by global warming are already causing massive die-offs of coral reefs, which are crucial sources of food and shelter for creatures at every stage of the ocean food chain, all the way up to us. Melting ice sheets are causing sea levels to rise, and if big ice sheets melt into the ocean, many coastal cities around the world will flood and millions of people will become refugees. There are just some of the consequences of global warming. Other predicted impacts include prolonged periods of drought, more severe flooding, more intense storms, soil erosion, mass species extinction, and human health risks from new diseases. The small number of people who experience better weather may be doing it in a landscape that is nearly unrecognizable.
Misconception 8
” The warming scientists are recording is just the effect of cities trapping heat, rather than anything to do with green house gases.”
→ People who want to deny global warming because it’s easier than dealing with it try to argue that what scientists are really observing is just the “urban heat island” effect, meaning that cities tends to trap heat because of all the buildings and asphalt. This is simply wrong. Temperature measurements are generally taken in parks, which are actually cool areas within the urban heat islands. And long-term temperature records showing just rural areas are nearly identical to long-term records that include both rural areas and cities. Most scientific research shows that “urban heat islands” have a negligible effect on the overall warming of the planet.
Misconception 9
” Global warming is the result of a meteor that crashed in Siberia in the early 20th century.”
→ This may sound absurd to some of us, but it’s real hypothesis suggested by a Russian scientist. So what’s wrong with it? Basically, everything. The impact of a meteor, much like a volcanic eruption, might have immediate effects on climate if it were large enough. But there is no record of warming or cooling during the period after this meteor hit. The effects that would have been produced by the meteor would have involved water vapor, which only stays in the upper atmosphere for a few years at the most. Any effects would have been short-term, and could not be felt this far in the future.
Misconception 10
” Temperatures in some areas aren’t increasing, so global warming is a myth.”
→ It is certainly true that the temperature is not rising at every point on the planet. In Michael Crichton’s novel The State of Fear, characters pass around graphs that show specific places around the world where temperatures are decreasing slightly or remaining the same. The graphs represent real data from real scientists. But while they may be fact, they don’t prove the point. Global warming refers to the rise in the average temperature of the entire Earth’s surface due to increased levels of greenhouse gases. Because the climate is an incredibly complex system, the impacts of climate change will not be the same everywhere. Some areas of the globe — such as northern Europe — might actually become colder. But this does not change the fact that overall, the surface temperature of the planet is rising, as are the temperatures of our oceans. The gains have been demonstrated by several types of measurements — including satellite data — that all show the same general results.
