For most students with an interest in the environment, anthropogenic climate change is an accepted fact, potentially being one of the biggest threats to mankind. Therefore, it’s easy to overlook the fact that many people still believe it’s a ‘hoax’; even some mainstream politicians (take the current Republican Party of America as a prime example) refuse to accept its reality. The rise of the internet has allowed a shocking spread of misinformation, which has further fuelled the flames of denialism. In this series of articles, I will look at some common arguments which refute the actuality of climate change and show how science can disprove them.
Climate change denialism is especially prevalent with people who identify as politically right-wing or far-right. That’s not to say left-leaning people are immune to it, but a recent poll in America found that only 18% of people who identify as conservative believe scientists think human induced climate change is occurring, contrasting with the 68% of liberals (left-wing) who think the same. People identifying as right-wing and far-right tend to have a distrust in governmental and international organisations, and many believe claims that climate change is a wealth redistribution programme built on fake science. Although these views may seem fringe to you and me, it’s a fairly common viewpoint in the USA and in many right-wing groups in Europe. The average rate of denialism varies between countries. In many US states as many as 40% don’t believe in climate change. The rates are much lower in European countries, with most countries polled showing more than 85% belief that humans are causing climate change.
Climate change deniers tend to use similar arguments over and over again and although many of these have some element of truth in them, they can be countered by sound scientific research. Let’s have a look at the most common:
‘The earth’s climate has been changing for thousands of years and to think that humans could have an effect on it is naive. The climate is changing but it is nothing to do with us. Science shows we are in a warming period after an ice age. The warming we are seeing now is just an example of that’
Many deniers accept that the earth is warming but blame it on natural changes over which we have negligible control. This claim definitely has some truth to it, as global temperatures have indeed fluctuated due to natural factors. Take the most recent glacial maximum as an example, which reached its peak 20,000 years ago. Scientists aren’t exactly sure what causes these temperature fluctuations, but it likely involves complex interactions between sun-earth dynamics (orbit and solar activity) and terrestrial factors (ocean and atmospheric circulation). During this period, global (average) temperatures were around 5.8 degree Celsius lower than modern times.
The Intergovernmental Committee on Climate Change (IPCC) predicts that current global temperatures are rising at a rate of 0.2 degree Celsius per decade and we could reach a warming of 1.5 degrees (compared to pre-industrial levels) by the year 2040.
So, the question is: how do we know that the warming we are experiencing now is not just part of a natural trend?
Well, the answer becomes apparent when you look beyond the total degrees of temperature change and instead look at the rate of the change. During the warming period after the last glacial maximum, the earth warmed on average between 0.8 and 1.4 degree Celsius, every thousand years. In the very long term, the change was quite severe, but it was a very gradual process! The change we are seeing now is more than ten times faster than the warming after the last glacial maximum, an event which caused parts of the northern hemisphere to effectively freeze over.
The warming after the last ice age also contributed to the extinction of many large species (‘megafauna’) including the woolly mammoth, sabre-toothed tiger and more. Although the change we are seeing in the modern day is unlikely to reach the magnitude of 5 to 6 degrees (hopefully mankind will act before that point), the fact that it could come close in such a short timescale should make it fairly clear that the warming we are seeing today is not a natural process.
Still not convinced? I’ll give you a thought experiment to help visualise the issue. Imagine if we accept that a 0.2-degree Celsius warming per decade is natural. 0.2 degree Celsius may not seem like a lot but if we scale that up to a 1000-year period, we would see a 20 degree warming. This means here in York, UK, we would see the average summer day temperature maximum rise from about 21 degrees to around 41 degree Celsius! The UK would effectively be turned into a desert and the entire globe would be reshaped, inevitably leading to mass extinctions and colossal environment disruption.
It is important to remember that a thousand years is still miniscule on a geological timescale. It may seem a lot compared to human generations, but it has been billions of years since the formation of the earth and 66 million years since dinosaurs roamed the earth. If we were to accept that this rate of warming could occur naturally, the result would be huge temperature changes over relatively short timescales (i.e., 40 degree Celsius over a timescale of only 2000 years), effectively rendering the earth almost uninhabitable. Very few animals and plants could tolerate that. Let alone humans.
Rather obviously, when we look back at the geological temperature record, we simply don’t see that magnitude of change in such short time periods.
Another argument against climate change is as follows: ‘The Little Ice Age of the 1300s saw temperatures drop naturally! Couldn’t what we are seeing now just be the converse of that?’
This links back to the point I made earlier, regarding the differences between natural changes and the unprecedented changes we are seeing today. Although the Little Ice Age did see temperatures drop across Europe, there are two important points that distinguish it from the climate change we are seeing today. Firstly, it was mainly a local change affecting only Europe (unlike the global temperature changes we are seeing today). It is possible other areas, such as North America, were affected as well; however, the changes occurred during different time periods (i.e., 17th Century in Europe and 19th Century in North America) indicating it was more a group of local changes as opposed to any widespread global cooling. Secondly, the magnitude of temperature change was lower (only a 0.5-degree Celsius global change) and there was nowhere near the consecutive decades of rapid temperature changes like we are seeing today. Despite its name, it was not a true ice age, it was simply a short period of slightly below average temperatures. Even so, the Little Ice Age had large effects, resulting in famines across Europe. This may be a worrying omen for how modern climate change could affect us all.
About the Author: Tom Wainwright is a 3rd year Natural Sciences student at the University of York. He thinks the world would be a better place if more people accepted climate change is happening.