By David Shukman
BBC science correspondent
If climate scientists are right, the past year's scenes of extreme weather are set to become commonplace by the end of the century.
The prediction is that by 2100, the average global temperature will rise by anything from 2 degrees Celsius to around 6C with potentially devastating consequences.
The question is, what should we do about it?
To help answer that, let's explore two different scenarios for our future world.
You could summarise the first option as "business-as-usual". We carry on living life as we do now, allowing emissions of greenhouse gases to continue to rise - and if the climate turns nasty, we put our faith in technology to come up with solutions for dealing with its effects.
So, the era of cheap mass flights continues unchecked. We go on enjoying the amazing choices of our advanced consumer society. And above all, we carry on our love affair with the car.
There's no doubt the car has become deeply ingrained in our lives - even though we all know it's a major cause of greenhouse gases.
According to Nigel Wonnacott, of the UK's Society of Motor Traders and Manufacturers, the car is now woven into the fabric of our society.
"It provides us with huge freedom and huge flexibility," he says. "What we need to do as an industry is ensure that the products that we deliver are as low-carbon as they possibly can be and that we as consumers use our vehicles, be they cars or vans, in the most environmentally responsibly way."
In any case, it's not just us and our cars that are pumping out greenhouse gases.
You could take the view that a far bigger problem is the vast emerging economies of India and China. By 2100, they will be pumping out carbon emissions at a far faster rate; and though we will affected by them, we may be powerless to stop them.
What would you do for a greener world?
Continue as before and rely on future scientific breakthroughs 17.36%
Be willing to sacrifice some consumer choices to slow climate change 82.64%
Results are indicative and may not reflect public opinion
As David Viner, of the Climatic Research Unit of the University of East Anglia, puts it: "We are going to see very high rates of emissions of greenhouse gases and as a result temperatures are going to respond accordingly and we will see very high rates of climate change."
One clear implication, he says, will be the impact on the sea-level and therefore the British coastline.
The Thames Barrier is the most visible symbol of our island's coastal defences and, under this scenario, if stronger defences are needed we will simply have to go ahead and construct them.
The Dutch, half of whose country lies below sea-level, have for years resorted to massive sea-walls.
If we choose to pursue the high-emission, high-technology path, then that too could be an option for us. It's do-able but very expensive.
We could also turn to new technologies like carbon capture - a system for trapping greenhouse gases. A pilot system in the Sahara - and another in the North Sea - captures carbon dioxide and pumps it deep underground.
With systems like this, you might take the view that the threat of climate change is perfectly manageable - and that our lifestyles can go on as normal.
But there is another vision for our future - an alternative option for a greener world. This would require some serious changes in our everyday activities.
The key would be a serious attempt to reduce our use of fossil fuels and to minimise the scale of the emissions of greenhouse gases.
Ready and willing?
Tony Juniper, director of Friends of the Earth, believes that the British public are ready to embrace the new approach needed.
Just as recycling has become part of our lives, so could thinking about how our actions affect the climate. It could be as simple as choosing energy-saving light-bulbs or having a range of domestic appliances that are all low-carbon.
"We should be looking at a choice of products that are the cleanest, greenest most environmentally friendly products. Now governments can accelerate that new world. It can be with us very quickly if governments put in place the regulations - and I think the public, by and large, would go along with this."
This greener future would require more fundamental change as well. For example, we have all come to like the convenience and huge choice found in supermarkets - but we also know the environmental cost of flying and trucking fruit, veg and other products from all over the planet.
Dr Viner thinks that our shopping would have to be "more local". Supermarkets would have to make way for farmers' markets.
"We would really focus on local production and local consumption," he says. "So in that respect we would be looking at a world where we are not flying around so much, where goods and services aren't being moved around the world."
And checking in for all those popular cheap flights would be a thing of the past - no more mass flying producing greenhouse gases. We would all be opting for a British holiday instead, getting back to nature and back to a low-carbon existence.
So there are the two scenarios: either, let's just carry on and depend on our boffins to sort things out; or each think about our individual impact on the climate and turn local.
We want to know what you think - because ultimately the choice is yours.
You can watch David's full report on BBC 1 at 0900 GMT on 31 December 2005.
What would you do for a greener world? Do you think we could control global warming through advanced science or is this unrealistic? Would you make personal sacrifices such as limited air travel, restricted use of cars and a more localised world? Send us your comments using the form below.