As promised:

Comment 19 by EvilConservative

There is NOT enough solid concrete proof to give evidence of Global Warming. There is NOT enough solid concrete evidence to prove "Man Made GW". There is NOT enough evidence to prove that GW does NOT exist.

There is little doubt that global warming is taking place. Thanks to the sceptical Professor Muller at Berkley, there is a definite warming trend over the last 100 years: http://berkeleyearth.org/

Yes the results are unpublished but they are in close agreement with the published results that Professor Muller was originally sceptical about because of a possible heat island effect.

As to whether global warming is man made - let's list the possible sources of warming (from a comment in http://www.nature.com/news/2011/111020/full/news.2011.607.html)

Natural causes:

Oceans: reorganization of ocean currents e.g. more fresh water in the North Atlantic

Continental drift: thousands/millions of years

Volcanic eruptions: sulphur dioxide causes cooling, insignificant quantities of carbon dioxide for warming

Earth orbital changes: discounted as changes happen over tens of thousands of years not hundreds

Solar variations: discounted as warming of the sun would cause warming of all the atmosphere (not observed) and not just the lower layers (greenhouse effect observed)

Man made causes

Carbon dioxide emissions (http://cait.wri.org/figures.php?page=/World-FlowChart):

1. 61.4% Energy (electricity, heat, transportation etc.)

2. 3.5% Industrial processes

3. 18.2% Land use change

4. 13.5% Agricultural

5. 3.6% Waste

Methane emissions

1. Animals

2. Landfill

Nitrous oxide emissions

1. Fertilizer

So - which of the natural forms of global warming do you believe is the culrpit?

30 years ago scientists were complaining about Global Cooling.

This was because of journalists (what again?) misinterpreting ice age cycles.