A while back, I had a very long discussion with several people over anthropogenic climate change. It took place on a video of Marc Morano and Bill Nye debating over the topic, thus I was bound to encounter quite a few people who are simply ill informed on the subject. Fate took hold and the bastions of idiocy and pseudoscience were brought before me, and I was placed in a position where I felt it was my obligation to clear the air of misconceptions and bad arguments that were being made by the global warming denialists. There was a lot of information passed around, so I wanted to take the time to place some of the arguments here and address them. Many of you will encounter these arguments at some point, so I want to be sure that my readers are well equipped with the knowledge to counter the folly.
If you want to read the full discussion, the thread can be found here. Quick note: denialist questions will be in bold, while my responses will not be. Beyond that, let's get started.
There is no consensus on global warming.
Of course, I've already addressed this before. Feel free to read into that as well as this post. I've heard some people counter by claiming that appealing to a scientific consensus is an appeal to popularity. Fortunately, no it isn't. Appeal to popularity refers to an uninformed public, or "just because a lot of people agree means that it's true." Appeal to scientific consensus is where we appeal to qualified experts in the relevant fields of research and ask for their views. If the overwhelming majority decide that global warming is real, and it's caused by humans, then it's our responsibility as laypeople to take their decision as fact. We have scientists for a reason, and that is so that the uninformed public has a panel or community of experts to go to on issues that they are unqualified in. If we start ignoring that community, we abandon rationality.
Temperatures during the Medieval Warm Period were hotter than today.
Locally, temperatures in some regions of Europe were hotter than they are today; however, this is not representative of the entire population. In Global Signatures and Dynamical Origins of the Little Ice Age and Medieval Climate Anomaly by Mann et al. (2009), researchers used a global climate proxy network of more than 1,000 tree ring, ice core, coral, sediment and other assorted proxy records spanning both hemispheres over the past 1500 years. They concluded that while in some regions, temperatures matched today's temperatures or may have been hotter, they do not meet global averages today. The trend is clear: global average temperatures have been rising at intimidating levels, and are hotter than ever before. For this point, the NOAA and the IPCC are great resources as well.
Global temperatures haven't risen in 16 years and counting.
This is just a fabrication. IPCC data clearly displays that global mean temperatures have been rising all the way up to the point of 2006. The year 1998 only ranks as the third hottest year on record, being bested by 2005 and then 2010. Even if it weren't a fabrication, it doesn't matter. We can take any period of time and say "there was no global warming from here to here" and pretend it disproves the overall trend; however, it just doesn't.
Weather reports are unreliable, so how do you expect to predict global climates?
I don't think I really need to hammer in the difference between climate and weather, but that's what it comes down to. Regardless of what variance there is in a particular region from day to day, we can still calculate global means based on the data available to us. If these averages show us that temperatures are rising at extraordinary rates, then we have reason to be cautious.
Aside from that, for what they're worth, weather reports aren't even that unreliable. They're just a lot more sporadic than climate models.
Global CO2 levels are not increasing.
Global CO2 levels are increasing. Some global warming denialists don't actually argue this point, but instead argue that rising CO2 levels don't matter. I'll look at a few of those arguments now.
CO2 is basically plant food.
I hear this one a lot, and it's not so much an issue of data as it is an issue of misconceptions. CO2 can be plant food, but not always. It depends on the plant, first of all, and even at that it only confidently works in a controlled environment (which, just for the record, the earth's atmosphere is not). Still, even if CO2 were basically plant food, that isn't a good thing. Growing plants means growing consumption of water and nutrients as well. Such a rise in consumption would result in the expansion of deserts, causing eco-zones to move towards the poles in search of a more suitable environment, and would eventually lead to the decline of those eco-zones. Ever hear of the phrase, "too much of a good thing is a bad thing?"
Global temperatures have only increased by one degree.
Yes, and one degree of global temperature changes can have a massive impact on ice sheets, sea levels, and many other things. All it took in the past to plunge us into the Little Ice Age was a 1-2 degree drop in temperature. People who use this argument are evidently superficial and unfamiliar with the scientific data.
And that's all she wrote.
I'd highly encourage global warming denialists to come here and make their arguments so that I can either expand the list or just refute the claims in the comment section. Come on, don't be shy!
And of course, thank you all very much for reading.
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Mann, M., Zhang, Z., Rutherford, S., Bradley, R., Hughes, M., Shindell, D., Ammann, C., Faluvegi, G., & Ni, F. (2009). Global Signatures and Dynamical Origins of the Little Ice Age and Medieval Climate Anomaly. Science, 326 (5957), 1256-1260 DOI: 10.1126/science.1177303