Average temperatures could rise by as much as 11 degrees Celsius around the world, twice that previously suggested, according to some scientists.
The Climateprediction.net project claims there is no such thing as a safe level of carbon dioxide.
During the World Economic Forum, Tony Blair insisted that an international consensus was emerging on climate change but governments could not be expected to push through changes that would damage their economic prospects.
What is your reaction to the latest prediction? Should something be done to combat global warning? What are your fears for the environment in light of these predictions? Send us your views.
This debate is now closed. Thank you for your comments.
The following comments reflect the balance of opinion we have received so far:
In spite of all the climate-change/peak-oil hype, nowhere in the world do I see any official moves to reduce dependence on cars. Everywhere it is business-as-usual. More and bigger vehicles being produced, glossily advertised and eagerly consumed. More roads being built to try and cope with unbelievably scary traffic-growth forecasts. Popular disdain for public transport and continued societal expectation that everyone should own a car. Equally scary growth-predictions for air-travel.. etc. Sure, there is justifiable scepticism over the some of the global-crisis scenarios, but what if it was proved beyond all possible doubt that our activities are destroying the place - would anyone change?
Dave, Wellington, New Zealand
Why has it been so difficult to move on from the carbon economy? With the technological resources at mankind's disposal today, it seems it should be a fairly easy thing to change to more eco-friendly sources of energy - solar, hydrogen, wind and so on. The progress made in developing alternative sources of energy is shameful slow. Hopefully, the threat of a global climatic meltdown will make us act. There is no other habitable planet nearby, you know!
Peter Wanyonyi, Nairobi, Kenya
On the one hand the government subsidises the building of wind farms as part of its claim to be environmentally friendly. Then on the other hand it approves more road building and massive airport expansion which will result in yet more car and plane pollution. This is a highly hypocritical, misleading and misguided policy!
Craig Belfield, Manchester, UK
We know from our own records that the land that is the UK now use to be tropical and very, very hot. Why cant people see that the climate change could be due to the natural warming and cooling of the earth? It's happened hundreds of times in the past every 50,000 years or so. I don't think its worth worrying about. We will run out of fossil fuels way before it could affect the environment. We are humans, we will just evolve and invent new technologies.
Carl, Northants, UK
If someone invented a non-polluting energy source tomorrow... it wouldn't help. Every person is a heat engine (we all generate body heat). Every home is full of electronic devices, each belts out heat. Even a non-polluting (as in emission chemicals) car engine would still generate heat. And the heat generated by industry (even if it produced no CO2) is phenomenal (when compared to before man was present on this planet). This problem is a lot more involved than anyone seems to realise.
Ian, Gloucester, England
The only source of energy that does not omit carbon waste is nuclear power. Although we don't have the technology to remove nuclear waste faster than about a thousand years in the long term this will cause less human suffering that an irreversible climate change caused or increased by carbon omissions.
Deb Stoddart, Newport, Wales
Stop using your tumble dryers and plant fruit trees in your gardens, so some of your food doesn't have to be transported across the globe. Both very easy to do and will actually help something, rather than just all this pointless talk.
The problem I see here is the mixed signals that we receive from the scientific community. Report A says we are damaging the environment, report B says we are not. Will someone make up their mind? It seems to me a lot of these reports are documenting possibility and not probability. It's possible I will win the lottery this weekend, but the probability is very low. It is basic risk management. Until there is a completed definitive study that is agreed upon by the scientific community no one will really take this issue seriously.
Rob Askew, Stevenage, UK
How about this, Why don't people get out of there cars and get some exercise or use public transport! Vehicles are also one of the biggest polluters, oh then again, people don't care. I can drive and even had a car but gave it up as it was expensive and I wanted to do my bit for the planet. Getting public transport is a pain but at least I am doing my bit. There are so many selfish money-greedy people in the world. Very sad.
Tidus, Wirral, England
I am angered and frustrated by most peoples' complacency and decadence when the question of climate change arises. Because it is happening in slow-motion (in human terms), many people I speak to associate too much inconvenience with changing their lifestyles, so they do nothing. The industrialised world simply must make changes today and governments must force this to happen: better to have a 'Nanny State' than no state at all...
Steven Teale, Newhaven, East Sussex, UK
I agree with reducing pollution but I think we're getting just a little bit ahead of ourselves by assuming everything is our fault. Our planet has been around for hundreds of millions of years, and we're looking back a few tens of thousands of years at best, and concluding long-term trends from this information. I think global warming could be prevented if scientists would stop spouting hot air in a bid to get another research grant - don't forget these are the people who assured us Thalidomide was safe.
The consequences of air pollution are crystal clear to any sane person on planet earth especially after the floods and droughts which have become frequent. We want less words and more actions on the part of world leaders in particular USA. Life is in real jeopardy. Being reluctant in ratifying Kyoto convention, in my view, is unbearable and unforgivable. If we destroy our home, we can build another, may be better than it, but if we destroy our planet, we can go nowhere.
Abdelhamid Bouziane, Theniet El Had, Algeria
Of course something should be done, but it won't. All the main causes of pollution are also the main generators of wealth - that's why the world's richest country is also the worst polluter. Money is power, and the money men are certainly not going to reduce their cash flow for something that will not have any benefit for them. Only lip service is going to be paid to global warming, especially when the Americans even refuse to believe there is a problem.
The Earth's ability to remove carbon dioxide from the atmosphere is most harmed by the destruction of rain forests. The most cost effective measure for improving the environment would be to simply pay countries containing rain forests to protect them. If this warning were proven to be true, the answer would still not be Kyoto because it doesn't address the destruction of the rain forests.
Saying the weather patterns are related to pollution seems like a stretch. But, there is definitely something that needs to be done to stop the destruction of our planet. Water supplies and air quality are in serious peril. And we know for a fact that these are necessary for human survival.
James, WI, USA
All these doom saying reports become direr all the time but they're based on flimsy evidence and methods, and a lot of speculation. I think the real fear is that western culture is being destroyed on roughly the same timetable as these predictions about climate, and these reports are simply a projection of that fear.
Chrisse, Houston, Texas
If we humans as a whole don't consider the damage we may be doing to the earth and reduce the potential damage before it affects us all by changing our ways then the earth will eventually remove us through it's own processes, it's an organic process, like the body, and it will clear the disease - us!
Pete, Norwich, UK
If there is to be allocation of carbon dioxide generation, it should be based on productivity, not population. Given the vast size and efficiency of the American economic machine, the one the whole world depends on for its own prosperity, it should be allocated by far the greatest percentage of permissible greenhouse gases. The world's climate could be cooled quickly and easily by replacing the hydroelectric power stations in Russia which dried up the Aral Sea, once the world's fourth largest inland body of water and removing or bypassing the dams which created the problem.
Nothing will happen until governments of the highest polluting nations take a firm stance and make some unpopular decisions. Unnecessary high-polluting transport (such as the ubiquitous 4x4s in built up areas) should be taxed into oblivion. We need to make more effort to cycle instead of drive but the roads as they are today just don't allow it because there are too many cars. Big businesses where applicable must be forced into becoming greener, even if we risk large companies relocating to countries where they can harm the environment at will. I predict nothing will be done about this until it's too late because it will harm our pockets, so I'm hoping that the scientists are being over-cautious.
Steve, London, UK
I am outraged. I would like to ask the leaders of all those nations who refuse to sign the Kyoto Treaty for whom they are chasing economic prospects? In a sense politicians have a rather short-term memory: all they are doing is not for themselves but for their/our children and for the generations following them.
Mary McCannon, Budapest, Hungary
I think the debate is over, it was unrealistic to expect any governments to change their approach, especially the US. Better to put some contingency plans into place so we can survive the changes this will bring about.
Rex Lester, Chessington UK
Why can't fast food restaurants serve food consumed in house on proper plates rather than disposable? It all helps...
Lee Newham, London, UK
To people whinging about 'gas guzzling' cars - we have volcanoes spewing out millions on tons of noxious stuff 24 hours a day every day of the year and I'm supposed to worry about my two inch exhaust fed via a hugely expensive catalytic converter running for about half a hour a day? I don't think so...
Phil, Milton Keynes, Buckinghamshire
The cost of better research to answer the question of what role humans have in rising temperatures is much cheaper than the cost of cutting carbon dioxide. So it makes good sense to settle the scientific questions first.
Peter Nelson, Boston, USA
We should all in our small ways be contributing to reducing emissions and to recycling and reduction programmes, and this should be made as easy as possible for us by national and local government arrangements. But we are fools if we think that the world should stay the same for us just because we inhabit it. The globe is a still evolving planet and cataclysmic change has been part of its history and development since it began. The only difference now is that we think we can predict future disasters and we think we know what we should do to minimise them. Our problem is that we are not willing to inconvenience ourselves to achieve this. But perhaps the world is due for another vast climatic change, and the end result may mean the world is better afterwards, even if we're not in it.
Population control is complicated by politics. The right believes that we all have the right to as many children as we like. The left sees "genocide" in any effort to control population. Without population control, global warming and many other large scale disasters are inevitable.
Bob, Taos, USA
As a professional scientist myself, it is no surprise that these predictions show a wide range of temperature increases. The atmosphere is a complex and highly variable system; you can't model exactly what's going to happen. However, this shouldn't stop us taking the findings seriously. The fact is, temperatures are rising and will rise, polar ice caps are melting and will melt, and weather is becoming more extreme and will continue to do so. We should be making personal lifestyle changes to cut the amount of CO2 we produce, and lobbying our governments to take man-made climate change seriously. But all this takes courage, discipline and self-sacrifice for a greater good, which are hardly the tell-tale characteristics of modern British society.
Heather, Stockport, UK
It is a shame that everyone seems to take the attitude that they don't care for one reason. They will not be around to suffer the consequences. If one thing has been learned, it is that society feels no remorse for ensuring the worlds youth are left to clean up our mess with climate, economy, poverty, disease and war. We seem to be fine to sit back and watch as the Four Horsemen ride into town.
Paul Girling, Toronto, Canada
So there are to be no changes that 'damage economic prospects'? Regulation of any type will have a negative impact on industry, as it will always be cheaper to pollute than to be environmentally friendly. Is this then an argument for scrapping all environmental laws? No, because governments should be passing laws to protect us, not big businesses.
Franchesca Mullin, Northern Ireland
No we shouldn't do anything. Nothing at all. I've been hearing these messages from scientists for the last 30 years. The messages all have three things in common: the studies are incomplete, they need more funding to complete them and they scare the public with wild claims in order to get those funds.
Joe Pendlebury, Hayling Island, England
We may not be able to completely prove that mankind is making a significant contribution to global warming but this is really about a risk we cannot take. Nobody seems to be seriously suggesting a return to the Stone Age but fools dismiss the environmentalists without even thinking. When such ignorance is commonplace our future looks bleak.
Griff, Cardiff, Wales
Not enough it being done by world governments. It is all talk and no action. More also needs to be done in educating people as a lot of people still don't know what they can do to make a difference. Putting tougher penalties on people who drive around in gas guzzling cars would be a start.
A, Swindon, UK
People can warn about climate change until they turn blue, however, the major private companies will only implement change if (a) it's profitable or (b) it's law, and there is a large fine for operating outside the law.
Of course it should! But human nature being what it is who in the developed world is going to forego their life of ease and privilege now because of a possible future that may or may not happen?
Something should be done, but it won't as long as world leaders are bought and owned by oil firms. By the time someone realizes it will be too late.
Dain, Washington DC, USA
Looking at the graphs on the organisation's website the change could just as well be almost non-existent. There is such a huge spread in results, from almost 0 to 11 degrees Celsius, that this hardly warrants any claims of more urgency for measures. If anything, it warrants making haste with the rest of the research to reduce the spread to at least that of already existing studies. I'm not claiming nothing should be done, on the contrary, but giving out warnings based on one extreme result of largely varying predictions is alarmist and not helping solid, scientific debate and policy making.
Peter Braat, Roosendaal, The Netherlands
We need to control our population levels responsibly, thus cutting down on all the problems this brings. If we choose not to do this then our population will be controlled for us, by the planet, and it will not be kind about it. Global warming is just one of the disasters waiting to happen.