This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic. Objection: Scientists can't even predict the weather next week, so why should we believe what some climate model tells us about 100 years from now? Answer: Climate and weather are really very different things and the level of predictability is comparably different. Climate is defined as weather averaged over a period of time, generally around 30 years. This averaging over time removes the random and unpredictable behaviour of weather. Think of it as…
This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic. Objection: Climate is an inherently chaotic system, and as such it can not be predicted. Answer: Firstly, let's make sure we define climate. Climate is generally viewed as an average of weather patterns over some meaningful time period. The number of years may vary and there are probably plenty of other finer points to quibble about in there, but the purpose of getting this definition out in front is to be sure we are safe in discounting the very…
This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic. Objection: According to the IPCC, 150 billion tonnes of carbon go into the atmosphere from natural processes every year. This is almost 30 times the amount of carbon humans emit. What difference will any reductions we try to do make? Answer: This is quite true that the natural fluxes in the carbon cycle are much larger than anthropogenic emissions. But in the natural process, for roughly the last 10K years until the industrial revolution, every…
This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic. Objection: It's clear from the ice cores and other geological history that CO2 fluctuates naturally. It is a bogus assumption that the rise happening today has to be from humans. Answer: Surely it is not so hard to believe that since we emit billions of tons of CO2 into the air and, lo and behold, there is more CO2 in the air, therefore the CO2 rise is our fault. But if this simple common sense is not enough there is more to the case than that and…
This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic. Objection: Natural variability is the null hypothesis and an anthropogenic CO2 warming effect needs compelling evidence before there is any reason to take it seriously. Answer: The null hypothesis is a statistical test and might be a reasonable approach if we were looking only for statistical correlation between increasing CO2 and increasing temperature. But we're not, there are known mechanisms involved whose effects can be predicted and measured.…
This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic. Objection: Global Warming has been going on for the last 20,000 years. Answer: It is quite true that 20Kyr ago the temperature was some 8 to 10oC colder than it is today, but it is highly arbitrary and dubious to simply draw a line from that point to today and say "Look! 20K years of Global Warming!". If you have look at this nice graph of temperature starting at a point when we were finishing the climb out of deep glaciation, you can clearly see that…
This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic. Objection: Newfoundland was so warm in the Medieval Warm Period that when the Vikings landed they called it Vineland and brought boatloads of grapes back to Europe. Answer: One can not infer a global climate from an anecdote about a single region, or even a few regions, you need detailed analysis of proxy climate indicators from around the world. These proxy reconstructions have shown that the Medieval Warm Period (around the time the Vikings were…
This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic. Objection: Greenland used to be a lovely hospitable island when the Vikings settled it. It was not until the Little Ice Age that it got so cold they abandoned it. During that time, it was clearly not the frozen wasteland it is today. Answer: Firstly, Greenland is just a part of a single region and as such can not be assumed to represent any kind of global climate shift. See the article on the Medieval Warm Period for a global perspective on this time…
This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic. Objection: If you look back over the last 600 million years you see that there really is not much correlation between temperatures and CO2 levels. Clearly CO2 is not a climate driver. Answer: While there are indeed poorly understood ancient climates and rather controversial climate changes in Earth's long geological history, there are no clear contradictions to greenhouse theory to be found. What we do have is an unfortunate lack of comprehensive and…
This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic. Objection: There was global cooling in the 40's, 50's and 60's even while human Greenhouse gas emissions were rising. Clearly, temperature is not being driven by CO2. Answer: None of the advocates of the theory of Anthropogenic Global Warming claim that CO2 is the only factor controlling temperature in the ocean-atmosphere climate system. It is a large and complex system, responsive on many different timescales, and subject to numerous forcings. AGW…
This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic. Objection: Sure, Oreskes found no one bucking the consensus, but her paper was overturned by Benny Peiser who did the exact same study and found very different results. Answer: True, Benny Peiser did attempt a similar study and submitted it as a letter to Science responding to the Oreske study. But for very good reasons, it was not published. Peiser claimed to find 34 articles that fell into his "reject or doubt the consensus view" category. This is 3…
This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic. Objection: The Hockey Stick graph, the foundation of global warming theory, has been refuted and shown to be scientifically invalid, perhaps even a fraud. Answer: The first order of business here is to correct the mischaracterization of this single paleoclimate study as the "foundation" of Global Warming theory. It is anything but! What is going on today is unique and is understood by study of today's data and the best scientific theories the experts…
This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic. Objection: CO2 levels are recorded on top of Mauna Loa...a VOLCANO!! No wonder the levels are so high. Answer: Yes, it's true, Mauna Loa is an active volcano.  In fact it's the biggest volcano on earth! So, should we suppose that Charles Keeling didn't know that? Well, no, he did know this. And using subtle scientific indicators like "wind direction" he was even able to ensure that his readings were not contaminated by any out gassing when it was…
This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic. Objection: Satellite readings, which are much more accurate, show that the earth is in fact cooling. Some very old news here, that's all. I wonder how long before this one stops being brought up? Answer: There are a few advantages to the satellite readings, mainly the more uniform global coverage and the fact that readings can be taken at different altitudes.  However, it is in fact a very complicated process which uses microwaves emitted by the…
This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic. Objection: The kind of drastic actions required to mitigate Global Warming will risk the destruction of the global economy and the deaths of potentially billions of people. Answer: Is this supposed to mean that the theory of anthropogenic global warming must be wrong?  You can not come to a rational decision about the reality of a danger by only considering how hard it might be to avoid. First things first, understand that the problem is real and…
This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic. Objection: Why should the US join Kyoto while India and China haven't? Answer: The United States puts out more CO2 as a nation by far than any other nation on Earth, including China and India. Considering the relative populations (1 billion+ for each of China and India versus 300 million in the US) the per capita emissions are many times those of either of these other countries. On top of that, this has been the case for the past 100+ years of CO2…
This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic. Objection: The Kyoto treaty, even if fully implemented, would only save us about a tenth of a degree of future temperature rise many decades from now. What a waste of effort! You can see for yourself here at Junk Science's website. Answer: There are three big problems with this claim. Firstly, this is really a red herring. The purpose of Kyoto is to establish an international mechanism for dealing with global warming by taking the first tentative…
This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic. Objection: The Earth has had much warmer climates in the past, what is so special about the current climate? It seems like a generally warmer world will be better. Answer: I don't know if there is a meaningful way to define an "optimum" average temperature for planet Earth. Surely it is better now for all of us than it was 20,000 years ago when so much land was trapped beneath ice sheets. But anywhere between the recent climate and the most extreme…
This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic. Objection: The alarmists were predicting the onset of an Ice Age in the 70's, now it's too much warming! Why should we believe them? Answer: It is true that there were some predictions of an "imminent ice age" in the 1970's but a very cursory comparison of then and now reveals a huge difference. Today, you have a widespread scientific consensus supported by national academies and all the major scientific institutions solidly behind the warning that…
This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic. Objection: One good volcanic eruption puts out more CO2 than a decade of human emissions. It is ridiculous to think reducing human CO2 will have any effect. Answer: Not only is this untrue, but it couldn't possibly be true given the CO2 record from any of the dozens of sampling stations around the globe. If this were true, that individual volcanic eruptions dominated human emissions and were causing the rise in CO2 concentrations, then these CO2…