When exactly will global warming happen?

Answer 1

Global warming happens after a period of global cooling. It is cyclical and has occurred over several times over the last millions of years. The cause of this cyclical phenomenon is unknown; except it is known that man is not the cause since it occured before man arrived on Earth.

Answer 2

It has been happening, we probably already prevented another ice age from occuring. But, its difficult to predict exactly how fast things will happen. First off, the IPCC says that global temperature will increase anywhere from 0.5 to 3.5 degrees C by 2100, and that sea level will rise between 0.2 and 0.6 m by 2100. But this is hard to predict accurately.
They have many different model based upon how much fossil fuels we will burn. But this is hard to know.

The Mauna Loa Observatory has us at a 384 ppm CO2 level, which is the highest it has been in over 400,000 years. It has definitely been much higher than this. During the time of the dinosaurs, it was between 2000 to 3000 ppm. Granted, at the time, there was no polar ice and the decidous forests extended all the way out to the poles. And before the dinosaurs existed, 400 to 500 million years ago, CO2 level could have been as high as 7000 ppm. So its not like we will die if the CO2 level goes up.

The problem with predicting these things is that at 384 ppm, our CO2 level has been going up 2 ppm per year based upon our rate fossil fuel use. It is estimated that 2/3rds of what we have burned has gone into the ocean and the ocean contains 90% of the worlds CO2. It would stand to reason that if we burn all the fossil fuels that was made since the time of the dinosaurs but not the amount that existed before the dinosaurs, we would reach the CO2 level and temperature level that existed then. The unknown is the oceans. As more CO2 gets dissolved in the ocean, the ocean pH continues to drop. It has dropped so far from 8.25 to 8.14 pH. And if you know anything about pH from titrations, the time is takes to go from 9 to 8 is ten times as long as it takes to go from 8 to 7. As the pH drops, CO2 solubility goes down. Also, as the temperature rises, CO2 solubility falls. So, it is possible that in the future the ocean will slow down in its absorbtion of CO2 and may even start to release it. Also, water vapor is even a stronger greenhouse gas than CO2. So this could be a runaway effect. But who knows how long it will take for the earth to heat up, once all the greenhouse gases are released, and how long all the greenhouse gases will take to be released.

Answer 3

That's one of the things no one knows.

Of course, it's already started. You can see it in the temperature data and the loss of ice in the Arctic, and on Greenland.

But I imagine you want to know when it will get really bad.

That depends on exactly how the "feedback mechanisms" work.

For example, when white ice melts in Greenland it exposes darker ground which warms up more. That's "positive feedback". And warmer water creates more clouds, which block the sun to some degree. That's "negative feedback".

We know a lot about global warming and have a huge mountain of data on the basic facts, but not very much about the feedback mechanisms. Most scientists make an educated guess that positive mechanisms will dominate and global warming will be even faster than we now think. But it's just a guess.

From the definitive IPCC report:

"Models used to date do not include uncertainties in climate-carbon cycle feedback nor do they include the full
effects of changes in ice sheet flow, because a basis in published literature is lacking."

http://www.ipcc.ch/SPM2feb07.pdf

What we also know is that it will take many years to start making a change in man's impact on climate. We need to start now.

Answer 4

It will happen as the planet want's it to.
It's a normal cycle of the planet. We can't do anything about it but hold on for the ride.

Answer 5

Depends on how we treat the planet. Anyways checkout my latest question for more detail.

Answer 6

never.