Why is Climate Change So Difficult to Understand?

Last Thursday I attended a talk by Professor Carl Wunsch of MIT, as part of the Climate Connections lecture series at Wolfson College.  As an Earth Scientist I am often frustrated by the misunderstandings, over-dramatisations and confusion surrounding the field of climate science. It was refreshing to hear a knowledgeable researcher speak with honesty and clarity about what we do know, what we don’t, and what this means for our future.

Understanding how the Earth’s climate works is arguably the most complex scientific problem facing us today.  Almost every aspect of our planet influences the climate; ocean circulation, weather patterns, plate tectonics, distribution of life, volcanism, to name but a few. A change in climate could in turn have an impact on all of these aspects. Although progress is being made, not many can claim even a basic understanding of how such a wide variety of factors interact with each other and the climate, and yet it seems everyone has something to say on the matter.

During his talk, Professor Wunsch outlined four key reasons why climate science is so hard for us to grasp.

1)      Confusion between ‘weather’ and ‘climate’

One cold winter is not the harbinger of doom.  Changes in temperature on year to year scales are not indicative of change in climate, however much researches attempt to link them to reduction in sea ice or changes in ocean circulation. It may turn out that this year’s cold spell is the beginning of our descent into a European ice age, but one year is a microscopic blip in the Earth’s climate history. Without careful analysis over extended periods of time (at least tens of years) we must assume that what we see is short term variation in the weather, not a long term shift in the climate.

2)      The human search for patterns

As a species, humans have evolved to understand the world in terms of cause and effect. This has aided us well in our struggle to survive.  However, it has the occasionally problematic side effect that we search for patterns and causality everywhere we look.  The Earth’s climate system is stochastic and cannot be understood in this way. That is to say that whilst there are many factors that can be shown to influence climate, it also has a completely random component.  This means that it must be understood in terms of probabilities and risk, not in absolutes.  Anyone who says “I know that the ice-caps will have melted in 100 years.” is lying, but they can say “I think that based upon the data I have collected there is a significant risk that the ice-caps will have melted in 100 years, and we should therefore do what we can to mitigate that risk.”

3)      Everyone is an ‘expert’

Most people have an opinion about climate change (I know I do!), including some in high profile positions of scientific authority.  The problem comes when they share their opinions as if they are experts on the subject. Everyone from Nobel Prize winning physicists to politicians weigh in on the debate. Unfortunately given the complexity and lack of human understanding of climate dynamics, they are unlikely to be any more qualified than you or I are to speak on the matter.

4)      The media

The general media has earned itself a reputation for over-extrapolation and misrepresentation of science, and particularly of issues relating to climate.  Professor Wunsch was happy to point out that some ‘tabloid journals’ are also culprits of dramatisation, not just the mass media.  Although some of the media do get it right, with a barrage of conflicting information coming at us it is hard to pick out reality from climate fiction.

The single most important fact in the climate debate is that in the geological past the Earth’s climate has been radically different – both far warmer and far colder – than today. Many have taken this as an argument that we have nothing to worry about; the climate changes all the time and our very existence is evidence that the earth can recover.  So why is anyone worried? Firstly, the majority of research indicates that atmospheric CO₂ is increasing at a greater rate than it ever has in the geological past.  Secondly, never before has our planet been occupied by seven billion humans whose future depends on the state of the Earth.

As Professor Wunsch often re-iterated, we do not have a clear picture about what will happen to the climate, even in the next 10 or 20 years.  What we do know is that the rate of the anthropogenic-induced rise in CO₂ levels is unlike anything the planet has experienced since the advent of life, and that the potential risk to us as a species outweighs the costs to us now if we attempt to do something about it.

Although I would not necessarily agree with every point that Carl Wunsch made, I thoroughly enjoyed his talk.  He was un-hypocritical and un-biased in his presentation of the evidence as evidence, and his own opinion as just that. He spoke as a scientist should; he was clear and honest about what can and can’t be drawn from the data, something vitally important in such a controversial topic, where so much is at stake.