What would happen to global temperatures and atmospheric CO2 concentrations if we stopped all CO2 emissions?

A really good book that directly addresses that question is "The Long Thaw", which was written by Dr. David Archer, a professor of geophysics at the University of Chicago. (Dr. Archer is also a realclimate.org scientist/blogger). What I have scribbled out below is an oversimplified "summary" of some of the material in that book.

If CO2 emissions were stopped today, the Earth could continue to warm for several decades until equilibrium was reached. Then you would see a very slow return to a 20th-century climate as the various CO2 sinks began to remove the excess CO2 from the atmosphere.

There are a number of CO2 sinks with different capacities and different CO2 "uptake" rates. The CO2 sink with the greatest capacity (geological weathering) operates on time-scales of thousands to millions of years. Faster CO2 sinks (biological uptake, oceans, etc.) do not have the capacity to remove all the excess CO2. So even if CO2 emissions were to stop today, the Earth's climate would be feeling the effects for several thousand years (with the worst effects lasting a few hundred years).

Yes ottawamike --

The temperature will continue to rise for decades even if the CO2 concentration is frozen at its current level. The Earth does not warm instantaneously in response to CO2 increases for the same reason that a pot of water put on the stove does not boil immediately. It's really not that complicated.

Note that a cessation of fossil-fuel emissions will not cause atmospheric CO2 levels to drop immediately. What's already emitted into the atmosphere will stay there for decades to millenia. So the Earth will not begin to cool immediately.

Radiative equilibrium simply means that the amount of energy radiated out to space by the Earth is equal to the amount of energy received by the Earth from the Sun.

Prior to the industrial revolution, the Earth was in radiative equilibrium (or very close to it). The Earth is now significantly out of radiative equilibrium. Thus the Earth will continue to warm until the amount of energy it radiates to space increases to match the amount of energy received from the Sun (per the Stefan-Boltzmann law).

This NASA article will clear up any confusion you have if you take the time to read and understand it:

http://earthobservatory.nasa.gov/Features/EnergyBa...

Also should note: It has been known for well over a century that CO2 absorbs infrared radiation and that increasing CO2 levels in the atmosphere *will* warm the Earth. This was demonstrated by laboratory experiments conducted by John Tyndall some 150 years ago. If the names Joseph Fourier, John Tyndall and Svante Arrhenius do not ring a bell with you, then you might want to spend some time doing some research. The science showing that CO2 is a greenhouse gas that warms the Earth goes back two centuries.

Edited to add:

To ottawamike, who is "still waiting for the science".

If you were really interested in learning about science instead of arguing about it (from a position of ignorance, I would add), you wouldn't be here asking people to spoon-feed you material you could easily look up yourself. Get off your lazy backside and do a little of your own homework. If I were your science teacher, I'd flunk you in a New York minute.

In

Earth's Energy Imbalance: Confirmation and Implications

Science 308, 1431 (2005);

James Hansen, et al.

Hansen states

"The observed 1880 to 2003 global warming is 0.6- to 0.7-C, which is the full response to nearly 1 W/m2 of forcing. Of the 1.8 W/m2

forcing, 0.85 W/m2 remains, i.e., additional global warming of 0.85 * 0.67 ~ 0.6-C is ‘‘in the pipeline’’ and will occur in the future even if atmospheric composition and other climate forcings remain fixed at today’s values."

and here

http://www.pnas.org/content/97/18/9875.full.pdf+ht...

he states "climate sensitivity implies a thermal response time of the ocean surface of 50–100 years"

So the answer as you already know and some apparently do not is, it will keep warming for many years.

Ottawa Mike said"- "The evidence shows that CO2 lags temperature rises"

Well that is half the story now isn't it?

The temperature would drop considerably and the glaciers would be on the march again. Ottawa would be buried under ice within 20 years after the passing of "thermostat laws". Nobody seems to want to acknowledge the fact that the entirety of recorded human history has been lived during an interglacial period of an ice age. Reduce CO2 emissions and the planet gets that much colder. It's a delicate balance, and one that is tipping towards too much CO2 and has been for some time now. Our efforts at industry warm the planet and keep us comfortable, but we are going too far with it. Jack down the emissions just enough, but not too much. Either way, we cannot keep the ice from coming back. It is inevitable.

What would happen if humans stopped all man made CO2 emissions from power plants, cars, and manufacturing? We would reduce the CO2 levels from the current 380 ppm to at most 300 ppm. That is if nature doesn't replace the amount that we decrease. The effects on temperature would be very small.

Dana, I love the ecohuddle link where all greenhouse gases are considered man's responsibility. My question is what happened to the 280 ppm that is baseline? Also, how much of the little over 100 ppm increase is from natural sources?

Absolutely nothing as humanity only produces a maximum of 0.0001% of the co2 in the atmosphere. The rest of the 100ppm difference between today and 100 years ago was released through out gassing from the oceans as they have been warmed by the sun over those years. So until the oceans cool off enough until they can reabsorb that witch they out gassed it is going to remain in the air.

The 100ppm release of co2 into the atmosphere has caused a reduction of pH from 8.5 more than 100 years ago to about 8.2 today. This is about normal because ocean pH is higher than fresh water because of its higher mineral content all of which is alkaline in nature.

im no scientist, but here is what i believe will happen from my past research and education

the earth will slowly begin to repair itself through the many cycles and eventually, the temperatures will go back to the norm. the climates will go back to what was excpected, and the seasons will go back to be when we predict and more closely to the calendars time of seasons. the co2 levels will decrease as long as we continue to take care of the planet.

it would take a long time though, there has been so much damage that it wont be cured overnight, or even in a year. it will take a very, very long time.

by 'all co2 emissions' im assuming you mean from man made mechanics such as cars, factories, ect. there will always be some co2 emissions for we give off co2 everyday as a means of breathing and consuming/releasing waste.

we do need to stop releasing so much co2 with our man made machines because it is throwing nature off balance

Then the overpowering natural co2 emissions coming from the oceans! the rotting matter, volcanoes, & other animals would take over!

There would hardly be any change if we stopped emitting co2!

Mike R, is that any worse than treating the earth like a worthless object? in a sense she IS our god. if the earth goes what do you think will happen to us. we will die off too.

to answer the question though, I imagine the climate would stabilize as more CO2 is absorbed through plants and trees.

There would be no dying off of trees since all living things exhale carbon dioxide. it's a very precise order, no? =D

though i have seen articles that pretty much conclude that once CO2 is formed, it's there forever. even if it's absorbed by trees. those trees die and all the CO2 is re-released

It would plummet to -300 at nights, like on the Moon

You're right that I'm confused. The evidence shows that CO2 lags temperature rises but now people are saying if CO2 levels off (i.e. man stops all emissions), temperature lags and will continue to rise (for decades??).

And what exactly is equilibrium? Has the CO2/temperature relationship ever been in "equilibrium"?

Edit: Still waiting for the science. That's the applicable science not a misdirection to the carbon cycle or a personal website.