"The climate has always changed"

The commonest statement from climate change deniers at the moment is "The climate has always been changing and therefore the present change has nothing to do with our CO2 emissions".

This is like a 60-a-day smoker who says "I've had loads of coughs in the past and they have always cleared up, therefore this present persistent cough has nothing to do with my smoking habit".


The scientific facts are:

1.  The greenhouse effect is real 
2. CO2 is a greenhouse gas
3. We have already increased CO2 levels by 40%
4. The earth surface temperature has already risen by nearly 1*C
5. Already we are seeing changes in heatwaves and floods. 
6. If we continue to pump CO2 into the atmosphere, we, our children and our grandchildren are going to suffer
7. One of the problems is that migration is going to increase hugely.

Point 7 is there because it seems, sadly, that migration is the only thing that the people who make the  "climate has always changed" argument seem to worry about.