FACT-CHECK TIME! A lot of misconceptions (13, to be exact) were confronted here with some solid facts. How solid? Heres what our fact-checkers found: CLAIM: Global warming wasnt happening so they changed the name to climate change. FACT: Global warming is technically correct; however, climate change indicates the wide range of problems (stronger storms, rising sea levels, ocean acidification, etc.) our planet is facing. CLAIM: The globe isnt warming. FACT: 13 of the 14 hottest years occurred this century. And the trend is even more clear when satellite data is included. CLAIM: In the past, scientists said the earth was cooling. FACT: Some scientists in the 1970s predicted cooling, but six times as many papers during the same period said it was warming. CLAIM: The earth is cooling. FACT: Its not just temperature that shows the warming. Sea levels are rising 3 mm a year, which indicates oceans are warming and, therefore, expanding. Also, Arctic sea ice is melting at unprecedented rates. CLAIM: Arctic sea ice is increasing. FACT: Look at the bigger data set, not just the latest little uptick, and youll see the overall trend is downward. CLAIM: The sun is responsible for warming. FACT: The sun was getting brighter in the 1930s, but since the 1950s, the sun has been getting dimmer — and yet, temperatures continue to rise. CLAIM: Humans emit only a tiny fraction of CO2. FACT: Thats true — 30 gigatons from human activity vs. 780 gigatons from natural processes. But the earth isnt in balance like it used to be, and current CO2 emissions are outpacing the balance. We know the increase is man-made because the isotope carbon 13, which is less common in fossil fuels, is dissipating in the atmosphere. In other words, were seeing more CO2 in the atmosphere, and its got the molecular signature of fossil fuels. CLAIM: Volcanoes emit way more CO2 than humans. FACT: Volcanoes emit about 0.25 gigaton, less than 1% of what humans emit. CLAIM: Water is by far the most potent greenhouse gas. FACT: Yes! But water in the atmosphere is increasing because the air is warmer. Its still a CO2 problem that creates a positive feedback loop. More CO2, more warming, more water, still more warming, and on and on... CLAIM: Predictions have failed. FACT: Most predictions actually agree with observations. A model from 1988 did disagree, but thats when we thought climate sensitivity was higher. If you rerun the model with 3 degrees of warming for every doubling of CO2, the predictions are right on. CLAIM: The earth has warmed and cooled in the past. FACT: Past changes were due to tilt, precession of tilt, and orbit of the earth — the Milankovitch cycles. CLAIM: CO2 lags behind the temp rise. FACT: 90% of temperature increases start after CO2 rises. CLAIM: Global warming isnt that bad. FACT: It means more intense weather, acidic oceans, and rising sea levels, along with a bunch of other terrible stuff. Wed be much better off just reducing carbon now, rather than paying the price later. youtu.be/OWXoRSIxyIU
Posted on: Fri, 10 Oct 2014 05:04:32 +0000
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