GLOBAL WARMING: A Team Debate.

R1) Anthropogenic Global Warming (AGW) ExistsRight from the start we can see a lot of errors from Con’s opening arguments and graphs. The first thing we want to note is that Con’s first graph about atmospheric CO2 levels is extremely misleading. Although Con doesn’t source it, Con’s graph comes from a study by Robert Berner. There are HUGE uncertainties in Berner’s guesses as to what CO2 levels were hundreds of millions of years ago. You can see in the chart below that the range of error is huge . [http://tinyurl.com...] Also Berner himself said that the “exact values of CO2 [in his report] should not be taken literally.” [SkS1, http://tinyurl.com...] Berner’s guess-work therefore cannot be cited as the actual values for CO2 levels in the past. Second, the sun was so much dimmer hundreds of millions of years ago that higher CO2 levels were needed just to prevent the Earth from freezing over. (During this period, the sun “would have been several percent dimmer according to established nuclear models of main sequence stars . . . with a dimmer sun, high CO2 is necessary to stop the Earth freezing over.”) [SkS1] Berner even said, compensating for all the factors that were different in the past, “over the long term there is indeed a correlation between CO2 and paleotemperature” [Berner and Zavareth 2001, http://tinyurl.com...]. Third, you can see that over the past 10,000 years, CO2 levels today are at an all time high. CO2 has risen exponentially since the start of the industrial revolution. [http://tinyurl.com...] Unlike over a time scale of millions of years, the luminosity of the sun has been relatively constant over the last 10,000 years, so the only factor that has changed has been CO2 levels. Therefore, the only factor that can explain the temperature increase over the last 10,000 years is CO2. Fourth, Con is blatantly wrong. The greenhouse effect is obviously a real effect that is acknowledged by every scientist in the world. When you walk into a hot car or an actual greenhouse, it has heated up so quickly because of the CO2 in the car or greenhouse. It is impossible to assert that CO2 levels have *no* effect on temperature. The following chart shows the correlation between CO2 and temperature over the last 500 million years. The dotted line is CO2 and temperature is the solid line. The study also concludes that if you look at the luminosity of the sun alone, without accounting for CO2 levels, luminosity alone *fails* to explain temperature fluctuations. [http://tinyurl.com...] Our opponents next cite Don Easterbrook, who predicts a cooling in the near future. However, his predictions have been outrageously incorrect for the first 10 years of its data. [SkS3, http://tinyurl.com...]. The following graph depicts Easterbrook’s failed predictions: [SkS3] You can see from the graph that temperatures have actually increased, not declined as Eastberbook predicted. Further, although Easterbrook portrays the IPCC’s prediction of the temperatures since 2000 as incorrect, the IPCC actually got the story much closer to reality than Easterbrook. When confronted as to where Easterbrook obtained the IPCC data, he claimed he got it from the website, but that they had deleted it. The data he portrays shows future temperature predictions based on greenhouse gasses alone, which is not the actual IPCC data from the IPCC reports (which included natural factors as well). In other words, Easterbrook’s model has failed to predict what has occurred and his refutations of IPCC findings refutes a dataset that the IPCC never even used in their report because it is not a complete picture of the causes of warming. [SkS4, http://tinyurl.com...]. R2) Sea levels and ice levels Con says that Al Gore said all the ice would be gone by now. We never cited Al Gore and there are a lot of unscientific things said in his documentary. Who cares what he said, Al Gore is not a scientist nor a viable source. Con drops the IPCC study that says ice levels will continue to decline in the future. Con also says that some Coast Guard boat is also seeing ice up north. We have never said there is zero ice anymore. Con is just straw-manning. Third, Con cites some sketchy tabloid-esque picture of the northern ice sheet. Taking 2 photos a year apart does not prove anything. You need to look at averages. If you take a photo on a bad day in 2012 and a really good day for the ice sheet in 2013, it might look like the ice sheet is increasing, but you have to look at annual average size, not the size on a particular date. It’s the same problem with saying “it’s cold outside today, so there’s no global warming.” If you measure global temperature on one day in 2012 and on one day in 2013 and say, “see the temperature has gone down,” that’s not proof that global temperatures are falling. Again, we need to look at yearly averages, not snapshots of a single day. Here is the *average* amount of ice in the ice sheet over time; it’s declining (because it’s melting). http://tinyurl.com... Next, Con cites Dr. Koonin, who didn’t say global warming doesn’t exist, but merely that climate models are uncertain. Something can still be a threat, even if the models are not accurate to 100% certainty. Con also notes that temperatures have not risen dramatically over the last 30 years. This is due to a series of El Nino events that have pushed some hot water from the surface into the deep ocean. [NOAA, http://tinyurl.com...] This effect will not continue forever; we just got lucky that ocean circulation shifts managed to shift some heat into the deep oceans. IPCC climate models that predict an increase in temperature of 2 degrees in the future account for these El Nino events. Con also says that sea levels have not been rising any faster than in the past. However, sea levels have been rising *twice* as fast over the last 20 years than they did in the preceding 80 years. [Nat Geo, http://tinyurl.com...] Con looks at an 8 year period and says the rate isn’t increasing, but the only reason that would be relevant is if the rate of CO2 emissions was a lot higher at the end of the 8 year period than at the beginning. If the amount of CO2 emitted by humans per year stayed relatively constant over this period, you wouldn’t expect sea levels to start rising any faster. Also, Con is merely cherry picking an 8 year period that looks favorable to them. If you look at trends over a broader time scale (100 years), the rate of increase has gone up. Con then merely straw mans our argument and says that if polar ice caps had *completely* melted already (something we never claimed), then French Guyana would be underwater. We never made this claim. We only said that some island nations, like Kiribati, have thus far been swallowed by the sea. [http://tinyurl.com...] R3) Global warming is, on balance, good First, Con can’t outweigh a threat. Nukes are a threat. On balance, mutually assured destruction may be beneficial to global peace, but nukes are still a “threat” to the United States. Even if something has some good effects, it can still be a threat. Second, Con’s points don’t outweigh the harms of global warming. (A) Health Effects Con claims that overall health would be positively impacted by higher temperatures. However, they don’t link their source (they cite a book, but don’t provide a link or a page number). There’s no scientific explanation for why strokes or respiratory disease would decline with warmer temperatures. Research has also shown that the severity of the flu virus would *increase* (not decrease) as temperatures warmed. Warmer winters lead to more severe flu outbreaks--which, by definition, means a warming climate would make flu epidemics more widespread and harmful [ASU, http://tinyurl.com...]. Con also claims that “extreme cold” has killed more people than heat waves. However, “extreme cold” refers to people who have died in blizzards or while backpacking. If you don’t prepare for the cold when you go outside, you’re going to die. In contrast, people don’t die in their houses because it’s too cold; they can always throw on more blankets. People without air conditioning, however, do die from heat waves. A 2003 heatwave in Europe killed 35,000 people (mostly elderly). [http://tinyurl.com...] On balance, “increases in heat-related deaths due to climate change would outweigh decreases in deaths from cold-snaps.” [EPA, http://tinyurl.com...]. (B) Economic Effects Con never proves that the benefits to crop outweighs the $1.9 trillion per year the US will lose due to global warming. Also, we already refuted these arguments last round. Con says that a “moderate” increase in temperatures benefits crops, but there’s no proof the increase will stay moderate and once it becomes too severe, crops are severely harmed. In addition, while crops grow faster in warmer climates, they grow too fast, leaving less time to mature, so they produce fewer edible byproducts. R4) Effects of CO2First, Con says we have prove that human-caused warming is a “substantial” part of warming, but we don’t have to prove it’s a substantial threat, just a threat, so this is *not* something we have to prove. The degree of danger from the threat can make it *more* of a threat, but a threat is still a threat. Second, CO2 has a cascade effect. When CO2 causes temperature to increase a little bit, that causes more evaporation from the oceans which leads to more water vapor in the atmosphere. So even if water vapor has the largest effect on global warming, CO2 emissions cause more water vapor to be released into the air, which is called a positive feedback loop [SkS2, http://tinyurl.com...] (“The amplifying effect of water vapor has been observed in empirical studies such as Soden 2001”). Third, Con is conceding the greenhouse effect exists in this contention, which destroys their first contention, where they are trying to deny that the greenhouse effect is even a real phenomenon.