GLOBAL WARMING: What Should We Do?

The Science of Global Warming

Experts are more confident than before that global climate change is in progress and at least some of the warming is due to human action. Over the last 50 years, the amount of CO2 in the atmospherehas risen 25 percent implying we will have warmer temperatures in the future. Global temperature rise by 2100 is estimated to be from 1.5o to 6o F. (During the ice age the global temperatureswere 8o F cooler than they are today).

Costs and Benefits of Global Warming

Costs

The costs are uncertain because the science is uncertain but best-guesses can be made:

Rise in average global sea level of 1 to 3 feet, flooding in coastal areas.
Air-conditioning and the required energy to power it will increase.
An increase in extremes of temperatures, i.e. more droughts, heat waves, floods, and fires.
A retreat of mountain glaciers.
Disappearance of some forests not able to migrate fast enough and corresponding disruption of ecosystems.

Benefits

Milder winters in northern climates.
Increase in rainfall in some regions and a corresponding maintenance or increase in agricultural production.
Increase in some year-round economic activity due to less disruptions from cold weather

The "Double" Externality Problem of Global Warming

The production of greenhouse gases is a classic case of a negative externality where the costs to the user are less than the social costs imposed on society as a whole. Externality problems, however, arise in two places: the individual and national levels.

Each individual and/or corporation has an incentive to emit greenhouse gases into the atmosphere because he/she receives the full benefit but does not pay the full cost. (Ex: driving clunker cars, using freon in a/c, burning coal, etc.)
Each nation has an incentive to emit greenhouse gases because the world must bear the full cost, but each nation bears only a fraction of the cost. This has created tension among nations especially since the biggest contributors to greenhouse gasesin the future are likely to be the poor countries today. (See article on China.)

It is unlikely that policies will be devised on a global level to adequately deal with global warming.

What Should We Do?

Should we act now and spend resources on something that might happen? Even if warming does occur, we don't have a good idea of the costs. They may be quite small. On the other ha nd, failing to act could lead to large costs on future generations because of our ignorance and selfishness. The costs of acting now may be far less than waiting a century until it is too late and much more expensive. Perhaps the best approach is to begin now (or continue) to reduce greenhouse gas emissions but not to jump in too fast until the benefits from preventing global warming become better known. For fear of future serious damage to the environment, however,one could argue that we should be cautious now and not wait until a crisis is impending.

Powerpoint slides corresponding to this lesson are available for viewing.