Well, what I want to focus on now is climate change, more specifically on the fact that climate change is a result of human activities. Now there has been some disagreement regarding the extent to which human activity can be blamed for climate change but I want to argue that there is evidence which clearly demonstrates that our own actions really are causing a genuine threat. The available evidence seems to indicate fairly conclusively that land and sea temperatures started to increase around 200 years ago. So, what's the significance of this! Well, 200 years ago roughly coincides with the beginning of the industrial revolution in the northern hemisphere. In other words, this was when our production of harmful gases really got going as a result of increased industrialisation. Since that time our production of gases has accelerated due to the fact that not only has industry grown in size but it has also now spread to the southern hemisphere, indeed, most parts of the world. So, in the last 200 years, as industry has grown we can see a gradual rise in the temperatures which, to my mind is sufficient proof of the damaging effect of our actions and needless to say it's an issue which we need to address.