THIS is the first of a series of three articles about climate change.

In this article I will try to explain the science of climate change and why it is now generally agreed that not only is the earth warming but human behaviour is responsible for that warming.

In the second article, I will explain very serious consequences that are likely to result if we do not reverse this trend, and in the final article I will attempt to set out measures that the local authority and the local community can take to, in some small way, mitigate the damaging effect of global warming.

As we all know, the Earth is warmed by the sun’s rays. They permeate through the atmosphere and are either reflected by the white surfaces (e.g. polar regions) or are absorbed into the ground and sea. Ground heat then radiates upwards and out through the atmosphere into space. This is a very basic summary of the cycle of heat coming into the Earth and then heat leaving the Earth.

In the past, when measured over an extended period, there has been a very rough equilibrium of heat entering and leaving.

The problem now is that certain gases hold heat within the atmosphere. As we increase the amount of these gases, more heat is retained and the earth’s temperature rises. These gases, (carbon dioxide, methane, nitrous oxide among others) are called greenhouse gases.

By our actions, humans are causing an increase in the greenhouse gases. The three main contributors to an increase in the greenhouse gases are burning fossil fuels, deforestation (trees absorb carbon dioxide) and certain forms of agriculture.

Many greenhouse gases last for a very very long period of time. So past emissions are still present in the atmosphere. Scientists are able to monitor carbon dioxide level up to 800,000 years in the past, and they tell is that the current levels are much higher than have ever been experienced before.

Over the last approximately 150 years, the earth’s temperature has risen by around 0.8°C. The rate of increase has quickened over recent years such that the rate of increase now is probably between 0.15 and 0.2°C per decade. This might not seem like much, but as I will describe in the next article, relatively small changes in the earth’s temperature can have serious consequences, both for us in Cumbria and for people around the world.