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As we sit in our livingrooms, buttressed against the cold by blankets, hot toddies, and cranked-up thermostats, it may seem easy to believe the assertions of those who say that global warming isn't real or those who say that it may be real but it's nothing to worry about. Hey, who doesn't love hot fun in the summertime? Maybe global warming will be our most successful export!
Well, not so fast there, Sly. Let's take a look at some data. In 2001, the Intergovernmental Panel on Climate Change (IPCC), an organization whose membership includes the US, released a report that included data and analysis about temperature trends, what's causing them, and what impacts we might expect to see. The graph below shows IPCC's scientific estimates of temperature changes over the last 140 years. The graph is a little techno-nerdy, but the most important part is the solid black line, which shows a clear increasing trend over the last century.
SOURCE: "Summary for Policymakers"—A Report of Working Group I of the Intergovernmental Panel on Climate Change, 2001
Some would still argue that scientists also know temperatures vary from year to year, and even long-term trends (over decades and centuries) in temperature can vary. Yes, this is true, but a quick look at the next graph should dispel any doubt that something very different has gone on in the last century, something indicative of a radical departure from past temperature variations and trends.
The plot below shows how temperatures over the last 1,000 years varied from the 1961-1990 average. Beginning in the early 1900s there is a steady rise up to the baseline period (1961-1990), and in the decade 1990-2000 the rise is even more dramatic. While the sharp rise in the last century is quite noticeable, the most important thing to see is that this rise contrasts sharply with the overall consistency of the previous 900 years.
SOURCE: "Summary for Policymakers"—A Report of Working Group I of the Intergovernmental Panel on Climate Change, 2001
OK, some would continue arguing: "So what? The increase is only a degree or two, and on a cold winter morning, that sounds OK to me."
But evaluating the impact of global warming is not as simple as the personal impact we might suffer from a degree or two increase. First, we must realize that the sharp upward trend in the last century—and especially in the last decade—predicts additional increases in the 21st century and beyond. Based on current data, the models predict and an increase of between 2.5 and 10 degrees Fahrenheit over the 21st century alone.
Some still may doubt that there will be a significant impact, saying that winters will just be a little warmer and summertime fun will spread to those unfortunates living nearer the earth's poles. Well, as a solution for some people's dislike of cold winters and their unrequited love of the beach, global warming will exact a very steep price. Here are some of the likely consequences of increased global temperatures:
- There will be major impacts to agricultural productivity. A recent government study estimates a 10 percent decline in yields of rice, wheat and corn for every 1.8 degree F increase in average temperature.
- Rising sea levels will submerge many near-sea-level island and coastal properties.
- Increasingly wild weather patterns will cause damage to property and agriculture.
- There will be better living conditions and expanded territories for disease carrying pests, resulting in increases in and spread of diseases like malaria, dengue fever, Lyme disease, and West Nile virus. The effect will occur globally, including Western nations.
Egad! Maybe all these bad results of climate change aren't worth the possibility of glimpsing an Eskimo babe in an itsy-bitsy teeny-weenie yellow polka-dot bikini.
Given that the IPCC has determined that the changes are mostly human-caused, we need solutions! And we will have them, in the next Eco-Logical.
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