whats the worst case scenario in global warming?

Answer 1

THE 20th century was warmer than any time in the past thousand years, but that is nothing compared with how hot the Earth could become over the next millennium.

If we burn all the fossil fuels that are left underground, the globe will warm by an average of up to 13 °C, according to the first serious assessment of how global warming might progress beyond 2100, the normal time frame of model predictions. That will wipe out most rainforests, destroy the fertility of many soils and leave the Arctic ice-free even in midwinter. London will be as hot as Cairo - except that, along with many of today's most populous areas, it will have been engulfed by an 11-metre rise in sea levels.


The atmosphere has been clogged with much more carbon dioxide than was expected, and the concentration has reached a level that scientists didn’t expect to see for a decade, according to stories by the Australian Broadcasting Corporation and Reuters, quoting Tim Flannery, the author of “The Weather Makers” and an accomplished Australian scientist.

Flannery got a peek at the latest Intergovernmental Panel on Climate Change report, set for release in November ahead of the world’s latest climate discussions in Bali a month later.

The number may not mean much to non-scientists who haven’t followed global warming closely, but the 455 parts per million of greenhouse gases in the atmosphere represents what is believed to be a critical threshold. At that point, the world is pretty well locked in to a 2 degree Celsius rise in average temperatures — enough to cause significant sea-level rise, and a cascade of other ill effects.

However, other climate scientists have said Flannery is mis-reading or mis-representing the data, and that the atmosphere is still near the 380 ppm mark. These scientists — not climate science skeptics, but themselves respected long-time researchers — say upcoming U.N. report is not expected to reveal any new data about the concentration of greenhouse gases, or the overall effect relative to cooling forces.

Scientists have been saying we should act to curb emissions before we hit 450 ppm, which scientists hadn’t expected to see for another decade, according to Flannery. He said the 455 ppm level was reached in 2005, and he accelerating accumulation of greenhouse gases is largely attributed to rapid economic growth in China, India and other developing nations. (Though, remember, the last 150 years’ worth of emissions came primarily from Europe, the United States, Russia and Australia.)

Answer 2

I found this study to be an interesting development, and a very timely one considering we're in the run up to Copenhagen. From a political point of view, I think it's useful in that it can be used to strengthen the green political agenda, partly because of the reputation of the Met Office as a trusted scientific organisation, although it might be seen as a little too timely considering Copenhagen, which may cause some to question it's reliability. The result is certainly at the higher end of predictions; a number of studies have predicted a possible 4C rise by 2100 [1]. I am aware that the Met Office has recently gained access to much improved climate models which may make their figure more reliable, though I don't know the details of that. As a worst case scenario it is possible as far as I am aware. In summary, its a good thing that the study has been produced. EDIT: In response to reading some of the other answer's comments, I agree that it is unusually timely, but, so long as the study has been peer reviewed scientifically, I don't really follow the argument that this is just hype.

Answer 3

The worst-case scenario is positive feedback of greenhouse gasses in addition to CO2, so that almost the entire infrared spectrum is blanketed. This would result in an approximate 30 C rise in average global temperature, a couple hundred years in the future. All the ice on the planet would melt within a few more hundred years, resulting in an ocean rise of 100 meters over present levels (leaving plenty of land uncovered). The habitable zones of the planet would move thousands of kilometers into the Arctic and Antarctic.

I point out that this scenario is not considered likely. There is, however, evidence that something like this occurred in the great Permian extinction, in reaction to rapid volcanic deposition of greenhouse gasses.

Answer 4

Global warming and peak oil double whammy, that is the more realistic scenario.

I'm an optimist though, global econmoic collapse due to the lack of oil for transportation. This will cause civil disorder as we realise why parts of Africa always seem to be in conflict. Population drops to a level sustained by localised resources and infrastructure.

Many areas are flooded due to positive feedback of global warming, this will cause broad migration, a more tribal society and greater sense of community.

The positive side is the handful of people with a knowledge of permaculture who can spread thier skills to a now keen to learn population, so allowing a small scale low resource, low pollution society to prosper.

Absolute worst case scenario is the Gia theory where we end up with a 'hot planet' with small settlements at the poles. These also would grow out of a knowledge of permaculture now being gained in semi-desert regions.

Answer 5

I'm not sure that there is such a thing as Global Warming, as one part of the earth warms up, another part cools down. This is part of a general cycle or pattern in our weather. Medieval England had temperatures very similar to what we can experience in some of the Mediterranean countries, ie; Portugal and Southern Spain etc. The only difference between then and now is the amount of pollution in the atmosphere and no one fully knows or can predict what effect this will have on the future of our planet.

Worst case scenario:

I wouldn't be too worried, man has survived ice ages and heat waves. We just need to cut back on pollution and try to live in harmony with the very thing that gives us life, Mother Nature.

Answer 6

Most orgabisms survive within a narrow temperature band, an increase of over 5 degrees will radically alter the balance of most ecosystems leading to mass extinction and a loss of natural resources; such as new compounds for medicines. The weather will change as climatic patterns are driven by the temperature difference between the equator and poles causing widespread storms, droughts, floods, etc. Crops will fail and the economy will suffer severely as a result of all this. Due to the increased temperature water become scarce as the evaporations rates will be higher but less rainfall, this may cause international problems as countries that have little water try to get it any way possible, (possibly war). In modern society people underestimate the inportance of water and how much we need to survive. The changes weather patterns are mirrored by ocean currents, fisheries will be damaged and the gulf stream may fail causing U.K temperatures to plumet, effectively a mini-'ice age' in Briton. There is much, much more, but lets face it no-one probably read this far anyway.

Answer 7

It depends on how much carbon dioxide we put into the atmosphere. If we could put as much as there is on Venus then conditions could be like those on Venus, hot enough to melt lead. Planetary observations first put scientists on to the problem. Comparing Earth with Venus and Mars, yielded some sticky facts. This led to Climate Change theory and it's confirmation by observation.

Most of the replies on this post are hysterical , you need to go back to the figures. NASA website should have something. It's probable that the weather will get more humid and stormy, many species of plants and animals will go. The coasts will have to cope with higher water levels. That's for starters, if we go on producing Co2 then the effects will be worse. The UK Stern report says it all, basically to do something would only cost less than 5% growth, to do nothing will be much more expensive.

Industries that adapt will make a load out of this, those that don't will die out. e.g. Toyota and Honda v. the Detroit dinosaurs.

Answer 8

Reasonable worst case.

Antarctica melts, sea levels rise 100 meters or so. The resulting flooding is so damaging the world goes into a serious economic depression. Damage to agriculture causes severe food shortages, millions in poor countries die of starvation. Positive feedbacks cause this to happen much sooner than anyone thinks, say 50 years.

Worst case. China stubbornly refuses to cut emissions, even as global warming is causing severe damage. Desperate nations declare war to make that stop. The war goes nuclear.

Not likely, it seems to be dawning on China that bankrupting the world with global warming will not be good for business.

Answer 9

The worst case would be an overall increase in world temperatures of around 5c. This would melt the ice caps resulting in land loss due to flooding.
The north Atlantic drift would be effectively turned off, resulting in norther Europe turning into a freezer.
As the temperature of the sea's increase there will come a point when the frozen methane stored at the bottom of the sea will be released, flash over and basically catch fire.
This will result in the sea's being on fire.
All human life will end.
But on the bright side of things for a few years we will all enjoy nice long hot summers.

Answer 10

Watch that epic movie, The Day After Tomorrow. There is hope, though. Remeber how those two guys were toasty warm in their tent, in the middle of the worst blizzard ever? All we have to do is find out what kind of tent they were using, and we'll all be fine. Also, we should start getting on better terms with Mexico, because according to the above mentioned movie, we will all be refugees down there, when the big storm comes.