SOCIAL INDICATORS 2006
There is a long history of environmentalism in American life. Yellowstone National Park was created in 1872. The Audubon Society, formed in 1905, was one of the earliest environmental groups. President Teddy Roosevelt (1901-1909) was probably the first "environmental president" with his conservationist policies. More modern environmental groups can be traced to events like the first Earth Day on April, 22, 1970. Conservation was reborn and concern about environmental issues become increasingly important factors in assessing quality of life.
Over the past fifteen years, global warming has become the central topic dominating the environmental debate. The concern is that industrialization has increased levels of “greenhouse gases” in the atmosphere and the temperature of the Earth is rising. This is believed to be responsible for everything from the polar ice-caps melting, to increased frequency of hurricanes, to extinction of species. Some environmentalists are calling for radical measures to reduce the production of greenhouse gases, most notably the Kyoto Protocol. So are we on the brink of a human induced disaster? Let’s take a look at some facts.
If burning of fossil fuels is responsible for the increase in global warming, than we should expect to see a noticeable rise in global warming correlated with the rapid increase of fossil fuel usage in the Twentieth Century. Have average temperatures risen over the last century? Yes. The average temperature has increased by about 2°C (less than 4°F.) But take a closer look at the average temperature history for the United States over the last century.
The real acceleration of greenhouse gas emission is believed to have started after World War II. Notice the trend line from 1910 to 1940. It is the steepest increase in temperature and it was before the greenhouse gases really got flowing. During the period of increased gas emissions from 1940-1970, the average temperature cooled! Since that time, the average temperature has risen albeit at a slightly slower rate than 1910-1930. Is there something else that might better explain this change? Take a look at the following chart:
This chart shows a remarkable correspondence between solar irradiation (dotted line) and temperature changes (solid line.) Also notice the CO2 levels charted in the lower right hand part of the graph and the lack of correspondence.
Earlier this year former Vice-President Al Gore made a movie called the Inconvenient Truth where he dramatized his conclusions about the impact of global warming. (See movie review.) One of the most frequently referenced parts of the movie is the "hockey stick" affect of global warming. Gore shows a wall length chart plotting the the annual global temperature for several centuries. We see minor fluctuations up and down until the late nineteenth century when the temperature begins and unabated rise until the present. Thus, the line on the chart looks like a hockey stick with a long straight handle and then the stick curves sharply upward indicating a rise in temperatures. If you have seen the the movie you know that Gore gets inside a elevator basket and raises himself in the basket. He uses his pointer to indicate how high on the graph the temperature will go if unabated. It is all quite dramatic.
What Mr. Gore failed tell us is that the temperature estimates he was using were based largely on tree ring data. When temperatures are warmer the tree rings get wider and when the temperature gets cooler the rings get narrower. However, temperature isn't the only thing that affects tree ring width. CO2 also affects the width of rings. Thus, when look at tree rings from the past century or two what he see is heavily influenced by increasingly levels CO2 not temperature change. Gore's hockey stick based on tree rings is merely telling us that CO2 levels have significantly increased but it tells us little about recent temperatures compare to past temperatures.
When take a historical look at temperatures using more reliable measures we see results like the following:
This data from the Sargasso Sea studies (the area of the Atlantic between the West Indies and the Azores) shows that we are actually emerging from a mini-ice age. Temperatures were much warmer in the Middle Ages then at present.
In short, global warming is more likely a product of the natural ebb and flow of the Earths ecology in relation to the activity of the sun. The predictions of a human induced catastrophe are more than a little exaggerated. In fact, increased levels of carbon dioxide may actually be beneficial in some ways. Plants feed on carbon dioxide and increased levels may contribute to plant growth and crop production for an expanding human population. Yes, there may be changes in sea levels and shifts in some weather patterns but could we stop them if we tried? The net pluses and minuses are not clear.
More intriguing than the climatology behind global warming, is the sociology and economics behind it. I wrote about last year in Publicly Funded Science, Global Warming, and Christian Responsibility. I will not recap that here. One website has a petition signed by nearly 18,000 scientists (as I recall) who reject the human culpability angle in the global warming dialog and reject the Kyoto agreements. (Petition Project) Much is made of consensus among scientists but science is not done by consensus. It is done by rigorous study that develops models with explanatory and predictive value. Those models do not exist and significant changes are introduced almost monthly.
This is not to say that there might not be harmful affects from pollutants we put into the environment (CO2 technically is not a pollutant). Clean and safe environments are important matters. Conservation is a desirable aim. Finding less toxic and more renewable sources of energy is important to the long-term well being of society. Finding effective ways of reducing waste is essential. From a geo-political standpoint, reduction in dependence on fossil fuels would greatly reduce the influence of unstable oil producing nations to influence world affairs. However, “crying wolf” only harms future environmental efforts and makes people cynical about legitimate environmental concerns.
The good news is that we are reducing our levels of pollution.
Emissions of the six principle pollutants dropped 25% between 1970 and 2001. Aggregate emissions have leveled in the past decade but per capita emissions are in decline. We have much room for improvement but we are hardly in an environmental apocalypse.
The nature of global warming is not as well understood as is often reported in the media and the human influence on the phenomenon is not clear. Global warming may bring some changes to our lives but radical changes to the world economy to stop the unstoppable will negatively impact the quality of life of millions of people around the world, especially the poor. Air pollution is in decline and quality of life with regard to the environment is stable if not improving in the US. However, major cities in some developing nations are horribly polluted and in need of cleaner technologies. We also can not turn a blind to eye to the impact "greenhouse gases" might have locally and globally. It is reasonable to conclude that excessive production of such gases could have a net negative effect on humanity and efforts to reduce them are warranted. That said, the apocalyptic claims of impending doom are overblown.