Playing roulette with the climate – everybody loses

07:55 May 22, 2009 PDT

The “roulette wheels” created by MIT researchers to show the range of probability of potential global temperature change over the next 100 years

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Research carried out by the MIT's Center for Global Change Science has predicted that global warming will be roughly double previous estimates – and could be even worse than that. While a major 2003 study indicated a median projected increase in earth surface warming of 2.4 degrees Celsius, the new study points to a median probability of surface warming of 5.2 degrees Celsius by 2100, unless drastic action is taken.

The worrying new projections were reached using the most comprehensive modeling yet carried out on the likelihood of how much hotter the Earth's climate will get this century. While other research groups have previously estimated the probabilities of various outcomes, based on variations in the physical response of the climate system itself, the model used by the researchers is the only one that also takes into account possible changes in human activities - such as the degree of economic growth and its associated energy use in different countries.

The study used the MIT Integrated Global Systems Model, a detailed computer simulation of global economic activity and climate processes that has been developed and refined since the early 1990s. The new research involved 400 runs of the model with each run using slight variations in input parameters, selected so that each run has about the same probability of being correct based on present observations and knowledge. The results not only indicated a median probability of surface warming of 5.2 degrees Celsius by 2100, but also a 90% probability of surface warming in a range of 3.5 to 7.4 degrees Celcius.

This figure is more than double the estimates provided by the 2003 study, with the difference attributed to several factors rather than any single big change. Among these are improved economic modeling and newer economic data showing less chance of low emissions than had been projected in the earlier scenarios. Other changes include accounting for the past masking of underlying warming by the cooling induced by 20th century volcanoes, and for emissions of soot, which can add to the warming effect. In addition, measurements of deep ocean temperature rises, which enable estimates of how fast heat and carbon dioxide are removed from the atmosphere and transferred to the ocean depths, imply lower transfer rates than previously estimated.

These factors and a variety of other changes based on new measurements and new analyses changed the odds on what could be expected in this century in the "no policy" scenarios - that is, where there are no policies in place that specifically induce reductions in greenhouse gas emissions. While the outcomes in the "no policy" projections now look much worse than before, the team says there is less change from previous studies in the projected outcomes if strong policies are put in place now to drastically curb greenhouse gas emissions.

The team also admits that the odds indicated by their modeling may actually understate the problem, because the model does not fully incorporate other positive feedbacks that can occur. For example, if increased temperatures caused a large-scale melting of permafrost in arctic regions and subsequently released large quantities of methane, a very potent greenhouse gas. Taking such feedback events into account would only make the odds much worse.

To provide a simple illustration of the range of probabilities revealed by the 400 simulations, the team produced a "roulette wheel" that reflects the latest relative odds of various levels of temperature rise. The wheel provides a very graphic representation of just how serious the potential climate impacts are.

The MIT team do stress that, due to the large number of uncertainties in the climate change equation, there is no way to make absolutely accurate predictions. All they can do is collect the best data they can, run the simulations and look at the spread of the odds. What the team is certain about, however, is that the least-cost option to lower the risk of climate change is to start now and steadily change the global energy system over the coming decades to low or zero greenhouse gas-emitting technologies. Let’s hope the odds of that happening rapidly improve.

Darren Quick

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User Comments (7)

Was this study done using the kinda flawed data, the really whack data, or the OMG I-can't-believe-that-garbage data that was pulled from where the sun don't shine? GIGO, people.

kwiebe

- May 22, 2009 @ 12:05 pm PDT

oooh... quick! Public interest in "Climate Change" is waning; crank up the calamity generators! Oh, but don't forget to put the problem at least a hundred years in the future so that no one ever sees any of it actually come true.

I mean, after all, this nonsense was being promulgated some years ago now and we haven't all sunk under the sea, starved to death, burned to a cinder or any other of the fanciful ways we were supposed to have met our doom... is it just me, or does anyone else ever notice that the Really Bad Stuff keeps being pushed out in time..?

"The sky is falling! The sky is falling!"

Xolin

- May 24, 2009 @ 07:05 pm PDT

Oh dear, kwiebe & Xolin;

Let me tell you a story.

In Jan 2000, when I first saw the 200 year plot of the CO2 levels in the atmosphere, my blood froze. (I had previously only seen the cute little 8-10 year seasonal saw-tooth plots of CO2 levels.)

You see, what *I* saw was a plot of the data points of a runaway positive feedback reaction. I recognised it from my years of training as an old fashioned radio technician, when you were taught the deep basics. ALL physical positive feedback reactions behave the same way. Before solid state electronic devices, where now each device contains it’s own current limiters, some portion of an electronic device would explode & burn if it was allowed to run away through (re-enforcing, bad) posative feedback. (The historical 'brown smell'.) Only protected by realisticly rated fuses.

The earth has no fuse.

Soon after seeing that graph I posted a forecast based on that chart; that *IF the Earth's CO2 production was stabilised by 2016 (now only 90 months away; by production from *all sources being >equalled< by absorption by *all sources) , then the growth RATE of atmospheric CO2 would start to reduce and the maximum *level* of atmospheric CO2 reached would peak at about 450-455 ppm by about 2050.

From the data points of the graph alone, if 450 ppm is the maximum level reached on the chart curve, then the runaway reaction *might be reversed. The reaction would be 'calmed down'. The level of CO2 might then very slowly return to a lower & relatively stable level. Side effects should be reduced, and possibly even eventually stabilised, even if at a higher level than in the past.

(end post part 01 )

Sqidge

- May 25, 2009 @ 06:05 am PDT

(pt 2, cont. )

Again, purely from the classical shape of this positive feedback graph, I forecast that the RATE of increase of changes (CO2 levels building from the year 2000’s 2 pmm/yr) would *increase - and eerrmm . . .

. . . it looks like they have. That is what this fragment of research, so slowly and painfully compiled, indicates. Back then I forecast 3 ppm/yr by 2015-2016, if no reversal actions were taken before then. Again, this purely from the classical shape of the graph of the data points, of what appears to be a runaway physical reaction of some sort.

I win!

We win? Probably not.

What is indicated here is that there is now no hope of equalising outputs & inputs by 2016.

There is an ancient Kharzak proverb that says something like; "He who does not know what occurred 7 generations before his time, and who does not plan for the next 7 generations, is a fool."

Welcome to the loony bin.

Jen Cluse

Brisbane Oz

Recent Oz Federal Gov Democrats candidate

Sqidge

- May 25, 2009 @ 06:05 am PDT

Oh Xolin, you forgot the fact the dueling paradigms of "it's too late, we need to take drastic action" and "just a little change on your part can change the world". The best part is that when nothing happens not only can the disaster be rescheduled, but the alarmists can claim victory.

Eddie Sarphie

- May 25, 2009 @ 07:05 pm PDT

When Global Warming had to officially switch to Climate Change, the adults left the show - having seen this shtick many times before. The kids and starry-eyed hippies stayed behind with their fingers crossed, hoping it was actually true.

Todd Dunning

- May 26, 2009 @ 08:05 am PDT

Bruce Lee could teach everyone something about the environment and energy future. You see, Bruce Lee believed in not wasting energy, but rather in the more simple and direct approach. I see a lot of wasted energy in climate legislation, carbon trading, renewable mandates, all of these measures are intended to steer us away from needlessly burning of fossil fuels and in a round about way steer investment into renewable sources. Meanwhile us consumers will be paying out the nose for a system that is likely to be manipulated for corporate greed much in the way recent energy trading systems have done for California's electricity and oil for the rest of us. The environmentalists see this as a necessary evil which will bring about their end goals eventually. Why not skip the beating around the bush, build nuclear power, build wind turbines, build solar power done. Why wear us out with AGW when we could simply focus on end goals we can all agree on.

TheDuke

- May 27, 2009 @ 06:05 pm PDT