Global Warming Is a Crisis
March 9, 2007 — -- When confronted with the power of a hurricane, a blizzard or theintensity of a heat wave, the idea that humans could control or eveninfluence the elements seems ridiculous, even arrogant. However, thanksto the development of industrial societies and the accompanying use of fossil fuels, that farfetched idea is becoming a reality.
Concentrations of carbon dioxide (CO2), methane (CH4) and other gases(all of which add to the greenhouse effect that creates a warmingblanket over the Earth) have increased sharply over the last century --by 35 percent for CO2, and by more than 100 percent for CH4. This is overwhelmingly due to humanindustrial and agricultural activity.
The conclusions from theoreticalstudies, direct observations and models are all quite clear and showthat these rising concentrations have led to a warming of theplanet over the last century. This warming can be seen in the weather station records, ocean temperatures, disappearing mountainglaciers, melting permafrost and retreating Arctic ice, and isbeginning to be felt in the statistics of extreme events.
There are other factors in climate change -- such as increases inparticulate pollution, changes in the sun or volcanic eruptions.However, even when you take all these into account the temperaturerise of the last few decades can only be understood if the warminginfluence of rising greenhouse gases is factored in. It is thisunfortunate fact that is at the heart of the global warming crisis.
It is true that the changes we have seen so far (thankfully) have notbeen globally disastrous. But three factors mean that our expectationfor the future is worse. First, CO2 put into the atmospherenow will continue to have a greenhouse effect for decades andcenturies to come. Second, emissions of CO2, which are soclosely linked to energy production, continue to rise at a rapidrate (around 2 percent a year). Finally, at concentrations which we are verylikely to attain in the coming decades, it will become increasinglydifficult to avoid temperature rises of 5 or more degrees Fahrenheitin the century to come.
Gavin Schmidt is a climate scientist at the NASA Goddard Institute for Space Studies. Scientific American magazine cited him as one of the 50 Research Leaders of 2004. For more information about the debate series, go to www.iq2us.org
What real difference do a few degrees of global warming make? That isa fair question, but to put it into perspective the global differencebetween the ice age and today -- when a mile or so of ice covered mostof New York -- was only 9 degrees Fahrenheit. In addition, the last time theplanet was likely more than a degree or so warmer than today, sealevels were around 20 feet higher due to significant melting of theGreenland and Antarctic ice sheets.
Regardless of future actions, some continued warming is inevitablesince the planet is still playing catch-up with what has alreadybeen added to the atmosphere. Changing emission patterns and technologywill take decades and so we are going to be adding significantlyto the warming "in the pipeline" over coming decades. We don't knowexactly what will happen. We don't know exactly where the thresholdsare. But the more warming there is, the more chances for somethingsurprising and possibly dangerous to occur.
The crisis comes about because if we wait until the consequences ofour actions are upon us, it will be too late to avert them. Only byacting with foresight and prudence can we possibly avoid the worstcase scenarios. Unfortunately this is a new kind of global problem.While individual countries already have difficulty in dealing withpredictable but long-term problems (such as pensions), no such issuehas yet been successfully dealt with internationally. Global warmingcan really be said to be the Social Security of environmentalproblems.
However, this is a challenge that can be met. Engineers have yet totruly think about the best ways to restrict emissions (there was noincentive before), societies have yet to assess the ways in whichtheir activities produce CO2 (or CH4 or the other climate-influencing factors) and these assessments have yet to be factored into currentdecision making. Once they start to be, and once there is a "price" toemitting CO2, myriad ways -- some as yet unforeseen -- will be found to avoid them.
Gavin Schmidt is a climate scientist at the NASA Goddard Institute for Space Studies. Scientific American magazine cited him as one of the 50 Research Leaders of 2004. For more information about the debate series, go to www.iq2us.org
Judging whether that will be sufficient is going to require continualmonitoring of the climate system and frequent revisions to the targetsand incentives that get put in place. Negotiations on those measuresare correctly the job for politicians and diplomats, not scientists.However, the scientists, through the Intergovernmental Panel onClimate Change, the National Science Academies of all the majornations and their professional scientific societies, have beenabundantly and plainly clear that global warming is indeed a crisis andthat steps need to be taken now to address it.
Gavin Schmidt is a climate scientist at the NASA Goddard Institute for Space Studies. Scientific American magazine cited him as one of the 50 Research Leaders of 2004. For more information about the debate series, go to www.iq2us.org