Climate change usually only comes up in the media and online when there is some progress on a small detail or when something like Copenhagen or the UEA email theft happens. I think that this presents a big problem as the people consuming these stories might not know the basic science yet, these days, everyone is expected to have an opinion on climate change. This issue is amplified on the web where George Monbiot’s column on the Guardian website, for example, regularly receives more than 1000, usually anonymous and often controversial, comments.
So I thought it might be a good idea to write a quick blog post for a complete climate science beginner. I’m only going to tackle two questions here, skipping over quite a lot of things, but they are the key points to understanding climate change.
What are greenhouse gases and what to they do?
All our planet’s energy comes from the Sun. Most of the radiation from the Sun goes straight through our atmosphere. When Earth absorbs the Sun’s radiation the planet heats up and then re-emits a slightly different type of radiation. The atmosphere can absorb this different type of radiation. This keeps some of the heat near the Earth like a blanket, or a greenhouse. The greenhouse effect is really important because without it the Earth would be much colder and our lives would be very, very difficult. Most of this science was known by about 1850 – we’ve been working on the details since then.
How has the concentration of greenhouse gases changed?
Ironically, also by about 1850, the Industrial Revolution had really got going and people were beginning to burn lots of fossil fuels and change the make up of our atmosphere. In particular, carbon dioxide was being released in great quantities. Our best measurements of CO2, however, didn’t start until the 1950s in Hawaii (see graph). This shows a really clear increase in atmospheric CO2. This increase is having an affect on global temperatures because the greenhouse effect is keeping more heat in than it used to.
This is the climate change problem described in its most basic form – more greenhouse gases lead to a change in the energy that is retained from the Sun. How this affects the Earth, though, is quite complicated (this why we talk about “climate change” more than “global warming” now) but the basic idea is quite simple.
Still want to know more?
If you still want to know more then I would say that the best place to start, as far as reliability and lack of agenda is concerned, would be the Intergovernmental Panel on Climate Change – this is a scientific group, organised by the UN, who review all the science relevant to climate change. This is obviously a massive task but, nonetheless, they publish their reports in full online – the last science report came in at around 1000 pages long. This is clearly not very easy to get to grips with. However, the do produce a short and well written Summary for Policymakers that covers most of the big issues. Also, they produce a Glossary where you can find the meanings of any terms you don’t understand. I really hope that more people go and find out more about the interesting science behind our planet’s weather and climate!