Resident Scholar Kenneth P. Green

A pessimist sees a glass half empty, an optimist sees a glass half full, and an engineer sees a glass twice as large as it need be. All three can be correct, in a situation where the glass really is half full. But, as your optimist points out, the glass of environmental improvement is well over half full, clearly making optimism the correct view.

In only 30 years since the beginning of the modern environmental movement, developed countries have seen massive improvements in air and water quality, soil and groundwater protection, reduced chemical exposures, waste reduction, biodiversity protection. . . . The list is virtually endless. And, as the optimist points out, although that's all been expensive, it's been done while increasing health, wealth, and opportunity. Because developed countries have market economies that generate prosperity, their residents could afford cleaner energy, better-insulated housing, and more efficient devices, reducing their individual environmental impact out of pure self-interest. And yes, they could even afford some regulations that slowed growth but helped spur environmental remediation.

There's no question that challenges remain: as your pessimist pointed out, we have badly mismanaged the world's fisheries and oceans, and since about 1975, humanity may well have contributed a bit of additional warming on top of a natural warming trend that has been proceeding since the end of the Little Ice Age around 1850. Plus, there's no question that developing countries face a massive challenge in both raising their standard of living and preventing environmental degradation that, because of their large populations, would be far greater than that of developed countries in historical perspective.

But although challenges still exist, that's no reason for pessimism: while cleaning up their acts, developed countries have also invented the technologies and wealth-building institutions that will allow us to solve remaining problems and let developing countries have their cake and eat it too. So long as markets and market-liberal institutions are allowed to function efficiently and spread, there is no reason to think the challenges that remain can't be handled even more efficiently than previous challenges were. And classical liberalism is spreading: the Heritage Foundation's Index of Economic Freedom shows a steady trend of increasing economic freedom around the world for the past 10 years.

Your optimist, in fact, may not have been optimistic enough. Barring a reversal of the trend toward economic freedom--the most serious threat to the environment--150 years from now, I believe people will be able to look back with pride at humanity's environmental performance. Yes, damage will have been done to the environment over a short term, but billions of humans will have soared through development in an eyeblink of evolutionary history, attaining a level of health, wealth, and opportunity undreamed of by preindustrial humanity. And looking back, we'll see that even while chasing development, we had both the awareness and responsibility to clean up as we went.

Kenneth P. Green is a resident scholar at AEI.