NEAR RECORD FOR 2002
Temperature data for the first 11 months of 2002 indicate that this yearwill likely be the second warmest on record, exceeded only by 1998. Thesedata from the Goddard Institute for Space Studies indicate that thetemperature for the first 11 months has averaged 14.65 degrees Celsius(58.37 degrees Fahrenheit), down slightly from the record high of 14.69 in1998, but well above the average temperature of 14 degrees Celsius thatprevailed from 1951 to 1980.
Studying these annual temperature data, one gets the unmistakable feelingthat temperature is rising and that the rise is gaining momentum. A yearago, we noted that the 15 warmest years since recordkeeping began in 1867had occurred since 1980. Barring a dramatic drop in temperature forDecember, we can now say that the three warmest years on record have come inthe last five years.
In addition to the longer-term annual temperature trend, recent monthly dataalso indicate an accelerating rise. In contrast to local temperatures, whichfluctuate widely from season to season, the global average temperature isremarkably stable throughout the year because the seasonal contrasts of thenorthern and southern hemispheres offset each other. The temperature forJanuary of this year of 14.72 degrees Celsius was the highest on record forJanuary. The 14.91 degrees for March made it the warmest March on record.And in seven of the next eight months--April through November--thetemperature was either the second or the third warmest. October was thefourth warmest.
Since 1980, decadal average temperatures have risen well above the 14degrees Celsius average for the span from 1951 to 1980, which is defined asthe norm. During the 1980s, the global temperature averaged 14.26 degrees.In the 1990s it was 14.38 degrees. During the first three years of thisdecade (2000-2002), it has been 14.52 degrees.
Rising temperature does not come as a surprise to atmospheric scientists whoanalyze the climate effects of rising atmospheric levels of carbon dioxide,the principal greenhouse gas. Each year since detailed recordkeeping beganin 1959, the concentration of CO2 in the atmosphere has climbed to a newhigh, making it one of the most predictable of all global environmentaltrends.
The rise in atmospheric CO2 levels is the result of massive fossil fuelburning that has simply overwhelmed nature's capacity to absorb carbondioxide. The temperature rises observed over the last two decades are inline with the results of research using computerized global climate modelsto project the effects of rising CO2 levels on the earth's climate.
The Intergovernmental Panel on Climate Change (IPCC), a group of more than1,500 of the world's leading climate scientists, reports that if atmosphericCO2 levels continue to rise as projected, the earth's average temperaturewill rise by 1.4-5.8 degrees Celsius during this century. The lower end ofthe projected increases would lead to a 0.14 degree rise in temperature perdecade during this century, roughly the same as during each of the last twodecades of the last century. But the higher end of the projected temperaturerange means an increase of nearly 0.6 degrees per decade, a rate that couldbe extraordinarily disruptive to both the earth's ecosystem and the economythat depends upon it.
There are many manifestations of a higher temperature other than thermometerreadings, including deadly heat waves, scorched crops, and ice melting. InMay 2002, a record heat wave in southern India with the temperature reaching114 degrees Fahrenheit (45.6 degrees C) claimed more than 1,000 lives in thestate of Andhra Pradesh alone. In societies without air conditioning, thereis no ready escape from the dangerous heat. To India's north, thetemperatures in Islamabad, the capital of Pakistan, soared to 117 degreesFahrenheit (47 degrees C) during June.
Farmers may now be facing higher temperatures than any generation of farmerssince agriculture began 11,000 years ago. Crop yields have fallen astemperatures have climbed in key food-producing countries, such as theUnited States and India. Many weeks of record or near-record temperaturesthis past summer in the northern hemisphere, combined with low rainfall,withered crops in many countries, and reduced the 2002 world grain harvestto 1,813 million tons of grain, which was well below the projectedconsumption of 1,895 million tons.
Crop ecologists at the International Rice Research Institute in thePhilippines have recently reported that rice fertilization falls from 100percent at 34 degrees Celsius (93 degrees F) to essentially zero at 40degrees (104 degrees F). Scientists in the U.S. Department of Agricultureare seeing a similar effect of high temperature on other grains. Thescientific rule of thumb is that a 1 degree Celsius rise in temperatureabove the optimum reduces grain yields by 10 percent.
One of the most sensitive indicators of higher temperature is ice melting.Scientists now report ice melting in all the world's major mountain ranges,including the Rocky Mountains, the Andes, the Alps, and the Himalayas. InAlaska, where temperatures in some regions have risen 5-10 degrees Celsiusover the norm, ice is melting far faster than had earlier been reported.
On Africa's snow-covered Kilimanjaro, the area covered by snow and ice hasshrunk by 80 percent since 1900. Lonnie Thompson, Ohio State Universityglaciologist, reports that all the snow and ice there may disappear by 2020.For Americans, another landmark--Glacier National Park--may be forced tochange its name. Half of its glaciers have already disappeared, and the U.S.Geological Survey projects that the remaining ones will disappear within thenext 30 years.
Scientists report that ice cover in the Arctic Ocean shrank to 2 millionsquare miles this summer compared with an average of 2.4 million squaremiles during the preceding 23 years. The thinning of the ice is proceedingeven faster. Since this ice is already in the water, its loss will notaffect sea level, but when incoming sunlight strikes snow and ice, 80percent of it bounces back into space and 20 percent is converted to heat.Conversely, when the incoming sunlight hits open water, only 20 percent isreflected and 80 percent is converted into heat, warming the region.
Scientists are concerned with this warming because Greenland lies largelywithin the Arctic Sea. This past summer ice melting occurred over 265,000square miles of the Greenland ice sheet-9 percent more than the previousmaximum. If the Greenland ice sheet, which is 1.5 miles thick in some areas,were to melt entirely, sea level would rise 7 meters (23 feet). What happensto the ice in the Arctic Sea and the climate in the region is of concern tothe entire world.
Some industries are beginning to respond. Worried about the loss of snow inmountainous regions and frustrated by the lack of progress in stabilizingclimate, the National Ski Areas Association, the U.S. trade association forthe industry, plans to soon announce its "Keep Winter Cool" campaign. To doits part to reduce carbon emissions, the industry plans to purchasewind-generated electricity to run lifts and snowmaking equipment. Othersectors of the economy, such as agriculture and the insurance industry, mayalso begin to press for a steep reduction in carbon emissions as the highcosts of failing to stabilize climate become unacceptable.
Changing the earth's climate is a serious matter, one that should not betaken lightly. The risk is that climate change could soon spiral out ofcontrol, leaving future generations with soaring temperatures, witheredharvests, deadly heat waves, melting ice, and rising seas. If we do not actquickly to stabilize climate, our grandchildren may never forgive us.
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Written by: Lester R. Brown, Earth Policy Institute
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