Question: climate change is really bad, and only recently have i descoverd the depts of the problems so my question is.. can/will there be a situation where the earth cools down , and does the opposite of what climate change is now? how long would it take ,if it were possible?

Hayley Evers-King answered on 11 Mar 2013:

There have been many times in the past when the climate has been different to how it is now – hotter and colder. There have been ice ages which are caused by the way the Earth moves on its axis and changes in its orbit. These effect how much energy we get from the sun and when this interacts with ocean currents and the way the continents are, the climate gets a lot colder. These ice ages happen in a cycle which last hundreds of thousands of years, so we are unlikely to see one soon. But there have also been some ideas that suggest we may delay the next ice age with our greenhouse gas emissions. Eventually the greenhouse gases we emit will be recycled through various processes on land and in the oceans, however the rate at which these happen is much slower than the rate at which we make the gases at the moment.

Other things in history have caused cooling – like volcanic eruptions and meteor impacts. A big event such as this could change our climate, but they are quite rare and many people think we would be silly to rely on an event to change the impacts we are having. Some people have come up with ideas that are similar to these natural events to try and change the climate ourselves. There have been some crazy ideas – like putting big mirrors in space and some less crazy ones, like creating more clouds and fertilising the oceans so they take up more carbon dioxide. These are very interesting ideas, but a lot of people think this sort of ‘geoengineering’ could cause more problems than it would solve.

Even with these types of events/ideas I don’t think there’s anything either in history or that I can think of that we could do, to oppose current climate change at the same rate as it’s being caused now. We still don’t know enough about the climate system to understand exactly how it will change in the future, perhaps this is job for you in the future? 🙂