Study: Emissions cuts can tame global warming

The worst of the global-warming effects can still be reversed, if proper steps are taken fairly quickly to reduce greenhouse gas emissions, according to an analysis by the National Center for Atmospheric Research.

A team led by Warren Washington, a senior scientist at NCAR's Climate and Global Dynamics Division, ran various climate-predicting scenarios with a Community Climate System Model run through a global supercomputer. Most notable is the simulation of what would happen in a world continuing on a path of unchecked human-made emissions of greenhouse gases versus one in which emissions are cut globally by 70 percent.

Supercomputer simulates how average Earth surface air temperatures could warm by the years 2080 through 2099, compared to the years 1980 through 1999, depending on whether greenhouse gas emissions continue to climb (top) or are reduced by 70 percent (bottom). Unchecked emissions could lead to an increase of 5.4 degrees Fahrenheit or more for parts of North America, Europe, Asia, and Australia.

(Credit: Geophysical Research Letters/modified by University Corporation for Atmospheric Research.)

The results by the year 2100 are a difference between the global temperature rising an average of 1 degree versus 4 degrees Fahrenheit; the sea level rising 5.5 inches versus 8.7 inches; and Arctic ice stabilizing versus having its thin seasonal layer melt away completely.

"The threat of global warming can still be greatly diminished, if nations cut emissions of heat-trapping greenhouse gases by 70 percent this century, according to a new analysis," according to an NCAR statement. "While global temperatures would rise, the most dangerous potential aspects of climate change, including massive losses of Arctic sea ice and permafrost and significant sea level rise, could be partially avoided."

The levels of greenhouse gas in the atmosphere have already risen from 284 parts per million (ppm) before the industrial revolution to more than 380 ppm this year, according to NCAR.

The computer simulation showed that if greenhouse gas emissions can be held at 450ppm--the target labeled as reasonably achievable by the U.S. Climate Change Science Program, if the world reduces emissions by 70 percent--the global temperature would rise by about .6 degrees Celsius (about 1 degree Fahrenheit) by the year 2100. If human-made emissions are left unchecked, the model predicted that greenhouse gas levels would rise to 750ppm by 2100, causing a global temperature increase of 2.2 Celsius (about 4 degrees Fahrenheit).

In the unchecked world, the model found that increasingly warm water temperatures would lead to a greater rise in sea levels, which, in turn, would lead to a negative impact on fisheries, sea bird populations, and mammals living in areas such as the northern Bering Sea. The simulation showed Asia, Australia, Europe, and North America as the areas that would see the greatest increase in average temperature.

It also simulated the U.S. climate specifically. In the world with 70 percent reduced emissions, for example, the U.S. Southwest would see double the amount of annual precipitation by the year 2100.

NCAR, which is funded by the Department of Energy and the National Science Foundation, will publish a full report on its findings next week in the journal Geophysical Research Letters. NCAR's report comes just as the U.S. Congress is about to debate the proposed American Clean Energy and Security Act of 2009, an energy and climate bill that would (among other things) impose a cap-and-trade system for carbon emissions permits and mandate increased use of renewable-energy resources for utilities.

"Our goal is to provide policymakers with appropriate research so they can make informed decisions," NCAR's Washington said in a statement. "This study provides some hope that we can avoid the worst impacts of climate change--if society can cut emissions substantially over the next several decades and continue major cuts through the century."

[ipashchuk]

"He who pays the piper calls the tune"

The simulation is based on the assumption that greenhouse gases trap heat, which is yet to be confirmed. The conclusion of the study is as good as its basic assumption.

[martin1212]

This is basic physics, it's been well known for over 100 years.

[TonyT11]

"The simulation is based on the assumption that greenhouse gases trap heat, which is yet to be confirmed. "

This is one of the dumbest statements I've heard in a long time. The greenhouse effect is a totally undisputed fact. You can argue about how much the increase of CO2 will contribute to warming if you'd like, but making statements like this only proves that you're completely ignorant about our planet's atmosphere.

[berad1989]

My only wish is that i had a time machine so i could take your naive ass 100 years into the future and show you how lovely its going to be. First off, greenhouse gases do trap heat moron. You probably dont even know how the greenhouse effect works in the first place. And secondly you should go take a look at a graph of the increase of green house gases from before the birth of christ through the industrial revolution onto this present day. After that, then you can say what you want about this article, because you'll no the truth just like me and every other sane person on this planet.

[iptofar]

If you believe computer models, I've got a nice rolex watch, only one owner in good condition for $100.

A 70% reduction is pie in the sky unless there is a global nuclear war. I'm not entirely sure that would be possible if we went back to manually farming the land.

The energy of a mixture of atmosphere gases can not be determined by temperature alone which makes what it promulgated erroneous and somewhat pointless.

The water in the air is a far larger contributor to global warming than CO2.

The level of CO2 currently in the atmosphere is equal to 2 feet out of a mile (0.0384%)

[berad1989]

You might possibly be stupider than the first dude i corrected. Your little theory about the "mixture of atmospheric temperatures cannot be determined by temperature alone" is so stupid i dont even know where to begin. But ill give u this little bit of advice my naive buddy. Go look at any atmospheric temperature graph for the past 300 years and YOU will be surprised to see that global temperatures boomed during the start of the industrial revolution (required an increase in fossil fuel burning), The civil war (required an increase in fossil fuel burning), World War 1 and 2, (ironically enough, also required an increase in fossil fuel burning). Now if u take all of those events and put them together you still wouldnt match the amount of temperature increase that has occured in only the past 20 years. Still dont believe its real? Because of unproperly educated people like yourself, this will become real. People like you and the moron above will be the ones to bring our climate to a breaking point, because you think "its not real". Open your damn eyes.

[ProNuke]

An obvious ignificant part of any solution, if there is one, is to build as many nuclear plants as fast as we can. The arguments against nuclear power are indefensible, but too many greens speak out of both sides of their mouths. The magnitude of CO2 required to reverse the trend is not possible when 5 billion people would like to live as well as Americans, so the rational course is to adapt to the coming changes as best we can. Buy northern Canada real estate!

[scottthesculptor]

Actually the southern hemisphere would be a better bet.

The coriolis affect at the equator separates the atmospheres of the Northern and Southern hemispheres - mostly.
Most of the "added ingredients" are floating around in the Northern hemisphere - as shown in the simulation.

But temperature doesn't indicate where the rainfall shifts will be . . .
More water vapor in the atmosphere as the temperature goes up.

[Atlas_]

Good luck getting the worlds largest CO2 producing nation to slow down, They are planning to output more CO2 than the rest of the planet combined by 2100. Which nation am I speaking of you ask??

CHINA - eco enemy #1 (last year they passed the US in CO2 output and are on track to pass the whole planet)

people in china are sick of walking and riding bikes, they want to DRIVE just like people in Europe and the USA. CO2 is an irrelevant consideration to them.

we are wasting our breath talking about reductions, the Chinese aren't listening

[finalfanoffkey]

Last time I checked, the Wall Street financial products are all based on the simulation of computer models, and the result is the country and the world is paying for it right now.

[shootfirst]

Simulations are meaningless unless someone else can prove the same thing given the same data. However we can have other things happen like super volcanoes erupting, asteroids pummeling the earth, or an alien invasion. We can cut back as much as they like and still be screwed. Forest Gump had it right Life is like a box of chocolates, you never know what your gonna get. Stop spreading gloom and doom to sell your products or up the price. Make something that is efficient and does the job at a good market price and is eco friendly and we will buy it, fail we won't. Stop playing a guilt trip on the world in which we the readers/consumers cannot possibly change by buying a different product.

[GODISMYSHADOW]

Yes, there are natural disasters that can beat us to it in ruining the planet. These could be the final hours
of a party, just before we get hit by an asteroid or some other horror from space.

[ProNuke]

This discussion can't succeed with a bunch of brief dueling comments, especially if I type as poorly as I did on my first comment. In any event, I'll add a few observations from my experience. I have seen a summary of the data required to support a credible global climate model. It is overwhelming, which probably explains why different models disagree with each other and can't replicate the known past. Also, thousands of reputable, competent scientists are in the "skeptic" camp, so skepticism can't be written off as the crusade of a bunch of whackos. They can't get federal funding, media attention or free trips to Fiji because skepticism is not the party line. Finally, as Atlas correctly noted, the Chinese and billions of others around the world want cars, clean water and so much that we take for granted that they will generate all the CO2 it takes, especially if the developed nations don't help them develop nuclear and other carbon-free energy sources to run electric cars and other first-world amenities.

[marc_90292]

Please forgive me, but given the mostly Republican objection to do anything about the climate, the discussion about global warming overshadows the crucial issue of national security. Emission is the result of fossil oil consumption. Our dependency on foreign - mostly hostile - suppliers is a serious threat to our national security as we have seen in the summer and fall of 2008. Only a Taliban sympathizer - or big oil - can be oblivious to the threat.

[Arno_Arrak]

To state that global-warming effects can still be reversed is to imply that there is warming, it is caused by carbon dioxide, and reducing it will reduce the effects of warming. But what if there was no warming? It would mean that carbon dioxide is a mere bystamder and efforts to reduce it amount to tilting at windmills. And that is exactly what we have: satellite data show that there was no warming of any kind in the eighties and nineties when that vaunted "late twentieth century warming" is supposed to have happened. But temperatures from this imaginary "warming" were fed into IPCC computers that gave us frightening forecasts of climate catastrophies to come. Garbage in, garbage out is unfortunately all what those computers were doing, Any talk of reversing global warming effects is based on the belief that GIGO actually means something. Check me out on ICECAP and get the facts. Arno Arrak