Warm Enough for You?
"Some say the world will end in fire,
Others say in ice...."
"Fire and Ice" by Robert Frost
Scientists have been warning us for several decades that the world is getting warmer as a result of burning fossil fuels (coal and oil), and that disaster looms. The threat of global warming was instrumental is development of the Kyoto Accord in 1997, in which signatory nations agreed to reduce emissions of carbon dioxide (CO2) and other gases.
President Bush does not believe that global warming is a threat, and has not recommended US approval of the Kyoto Accord. Who is right?
Q1. Is the world getting warmer?
From about 1880 to 1980 the average global temperature was about 57 degrees Farenheit (F); today it is nearly 58 F.
Of the 20 hottest years since records have been kept, 19 have been since 1980.
As recently as 1996 about 22 cubic miles of Greenland glacier ice melted each year; this year about 53 cubic miles will melt.
The percentage of the earth that is desert has more than doubled since the 1970's. (1)
Q2. What is the role of CO2 in global warming?
Carbon dioxide in the air does not block the sun's rays from warming the earth, but does inhibit heat from radiating from the surface of the earth back into space. Therefore the more CO2 is present in the atmosphere, the warmer the earth gets.
Q3. Is the concentration of CO2 increasing?
At the end of the last Ice Age there were about 180 molecules of CO2 per million molecules of air (ppm); in 1850 there were about 280 ppm; today the figure is
381 ppm.
Q4. What explains the big increase in the concentration of CO2?
Until about 1850 emissions of CO2 from burning were low and stable. By 1950 burning of fossil fuels was putting about 1.5 billion metric tons (mt) of CO2 into the atmosphere each year; last year more than 7 billion mt of CO2 was dumped into the air.
Q5. Is the increased level of CO2 responsible for the rise in average global temperature?
Possibly. But if so, why did the temperature remain stable until about 1980, even though emissions were rising for more than a hundred years before that time?
We know that global temperatures have fluctuated throughout time, long before human activity could have any effect. The last Ice Age was ended by a prolonged period of global warming, despite a relatively low level of CO2 in the air.
Q6. How does melting of glacial and polar ice affect world temperatures?
Ice reflects about 90% of the sunlight back into space, but water reflects only 10%.
Therefore melting of polar ice means that more of the sun's heat is retained by the earth, which in turn causes more melting, and so on.
Water from melting ice is not salty, so it reduces the salinity of the oceans. If the salinity is reduced enough, it will interfere with the water-cycle of the Gulf Stream, which now warms Europe. Ironically, global warming could actually make Europe colder if this happens.
Q7. How would melting of polar ice affect the human habitat?
Water pouring into the world's oceans would raise sea-levels around the world, inundating shores. Many of the world's great cities (such as New York, Los Angeles, Tel Aviv, Sao Paulo, and Miami) could lose big swaths of waterfront land to flooding, thus driving up prices for lands with higher elevation. In the US, mid-continental areas (such as Wisconsin) would attract millions of people from the coasts, thus driving up real estate values.
Q8. Would anyone benefit from global warming?
Yes. Residents of northern states, Canada, Scandinavia, and Russia would find the winters milder and more tolerable. (Haven't the last few winters in Milwaukee actually been milder than before? It seems so to me.) Farmers in these regions would have a longer growing season, and so could produce more.
Q9. What can be done to reduce CO2 emissions? Should the US sign the Kyoto Accord?
Switching from coal and oil based electricity -generation to nuclear power and switching to electric (or hybrid) cars could make a big difference in the long run.
The Kyoto Accord would sharply restrict US emissions, but not those of China and India which are rapidly increasing the use of fossil fuels. Since the US produces onlly 25% of the world's "greenhouse gases", even reducing our emissions to zero would not solve the problem. Unless it is amended to be fair to the US, we should not sign it.
Q10. If we keep on burning the same fuels at the current rate,
will global warming escalate?
Nobody knows. Although increased CO2 in the air certainly has a warming effect, its impact could be swamped by other factors that reduce temperatures. From 1973 to 1975 scientists warned that " a major cooling of the climate is widely considered inevitable.....global cooling may mark the return to another Ice Age." (2)
The rise in global temperatures detected since 1980 has apparently had a "chilling effect" on such predictions, but there is no reason to believe that climatologists today are any smarter than they were some thirty years ago.
-----------------------------------------------------------------------------------------------
(1) All numerical data are from "Global Warming", Time Magazine, April 3, 2006.
(2) New York Times, 1975.
Others say in ice...."
"Fire and Ice" by Robert Frost
Scientists have been warning us for several decades that the world is getting warmer as a result of burning fossil fuels (coal and oil), and that disaster looms. The threat of global warming was instrumental is development of the Kyoto Accord in 1997, in which signatory nations agreed to reduce emissions of carbon dioxide (CO2) and other gases.
President Bush does not believe that global warming is a threat, and has not recommended US approval of the Kyoto Accord. Who is right?
Q1. Is the world getting warmer?
From about 1880 to 1980 the average global temperature was about 57 degrees Farenheit (F); today it is nearly 58 F.
Of the 20 hottest years since records have been kept, 19 have been since 1980.
As recently as 1996 about 22 cubic miles of Greenland glacier ice melted each year; this year about 53 cubic miles will melt.
The percentage of the earth that is desert has more than doubled since the 1970's. (1)
Q2. What is the role of CO2 in global warming?
Carbon dioxide in the air does not block the sun's rays from warming the earth, but does inhibit heat from radiating from the surface of the earth back into space. Therefore the more CO2 is present in the atmosphere, the warmer the earth gets.
Q3. Is the concentration of CO2 increasing?
At the end of the last Ice Age there were about 180 molecules of CO2 per million molecules of air (ppm); in 1850 there were about 280 ppm; today the figure is
381 ppm.
Q4. What explains the big increase in the concentration of CO2?
Until about 1850 emissions of CO2 from burning were low and stable. By 1950 burning of fossil fuels was putting about 1.5 billion metric tons (mt) of CO2 into the atmosphere each year; last year more than 7 billion mt of CO2 was dumped into the air.
Q5. Is the increased level of CO2 responsible for the rise in average global temperature?
Possibly. But if so, why did the temperature remain stable until about 1980, even though emissions were rising for more than a hundred years before that time?
We know that global temperatures have fluctuated throughout time, long before human activity could have any effect. The last Ice Age was ended by a prolonged period of global warming, despite a relatively low level of CO2 in the air.
Q6. How does melting of glacial and polar ice affect world temperatures?
Ice reflects about 90% of the sunlight back into space, but water reflects only 10%.
Therefore melting of polar ice means that more of the sun's heat is retained by the earth, which in turn causes more melting, and so on.
Water from melting ice is not salty, so it reduces the salinity of the oceans. If the salinity is reduced enough, it will interfere with the water-cycle of the Gulf Stream, which now warms Europe. Ironically, global warming could actually make Europe colder if this happens.
Q7. How would melting of polar ice affect the human habitat?
Water pouring into the world's oceans would raise sea-levels around the world, inundating shores. Many of the world's great cities (such as New York, Los Angeles, Tel Aviv, Sao Paulo, and Miami) could lose big swaths of waterfront land to flooding, thus driving up prices for lands with higher elevation. In the US, mid-continental areas (such as Wisconsin) would attract millions of people from the coasts, thus driving up real estate values.
Q8. Would anyone benefit from global warming?
Yes. Residents of northern states, Canada, Scandinavia, and Russia would find the winters milder and more tolerable. (Haven't the last few winters in Milwaukee actually been milder than before? It seems so to me.) Farmers in these regions would have a longer growing season, and so could produce more.
Q9. What can be done to reduce CO2 emissions? Should the US sign the Kyoto Accord?
Switching from coal and oil based electricity -generation to nuclear power and switching to electric (or hybrid) cars could make a big difference in the long run.
The Kyoto Accord would sharply restrict US emissions, but not those of China and India which are rapidly increasing the use of fossil fuels. Since the US produces onlly 25% of the world's "greenhouse gases", even reducing our emissions to zero would not solve the problem. Unless it is amended to be fair to the US, we should not sign it.
Q10. If we keep on burning the same fuels at the current rate,
will global warming escalate?
Nobody knows. Although increased CO2 in the air certainly has a warming effect, its impact could be swamped by other factors that reduce temperatures. From 1973 to 1975 scientists warned that " a major cooling of the climate is widely considered inevitable.....global cooling may mark the return to another Ice Age." (2)
The rise in global temperatures detected since 1980 has apparently had a "chilling effect" on such predictions, but there is no reason to believe that climatologists today are any smarter than they were some thirty years ago.
-----------------------------------------------------------------------------------------------
(1) All numerical data are from "Global Warming", Time Magazine, April 3, 2006.
(2) New York Times, 1975.
posted by Gerald S Glazer at 5:58 PM
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