Thirty six years after the first Earth Day, there is much environmental progress to celebrate. Since 1970, lead emissions are down 98 percent, particulate emissions are down nearly 80 percent and sulfur dioxide emissions have been cut in half. All of this has been accomplished despite a doubling of the number of cars on the road and a 75 percent increase in coal-fired power generation. Progress since Earth Day is living proof of what can be achieved when governments, companies, investors and consumers all pull together.

Yet on global warming, there is no such harmony of thought or will. Some are still not convinced that the problem is real or serious, or that if it is, the remedies are too costly to implement. Meanwhile, carbon dioxide emissions have climbed relentlessly since 1970 -- up almost 20 percent -- and global temperatures have risen by 1 degree Fahrenheit.

And here's the most troubling part. In the decades leading up to Earth Day, fossil fuel emissions were completely unfiltered -- no scrubbers on power plants, no catalytic converters on cars. The result was visible air pollutants that shrouded the atmosphere in haze and produced reflective clouds that allow less sunlight to reach the Earth. This "cooling effect" has been measured at 1.5 watts per square meter, offsetting more than half of the warming effect of greenhouse gases, now equal to 2.6 watts per square meter.

As we rid the atmosphere of these visible pollutants in our post-Earth Day world, the warming effect of invisible greenhouse gas emissions is growing more apparent. This may be one reason why all 10 warmest years on record have occurred since 1990 (in a temperature record dating back to 1861). And why the rate of warming is accelerating, with global temperatures projected to rise possibly five or even 10 degrees higher by the end of the 21st century.

So despite all of the accomplishments since Earth Day, the problem of global warming isn't going away; in fact, steps being taken to clean our air may be making it worse. Ways must be found to get at the root of this problem -- and soon -- in order to slow and eventually reverse the growth of carbon dioxide and other greenhouse gases. This will require energy and technology innovations that dwarf the remarkable environmental achievements of the last third of a century. And once again it will require governments, companies, investors and consumers all pulling together.

If there is a silver lining in this, it is that tremendous investment opportunities await those who anticipate a world less reliant on carbon-emitting fossil fuels. With new concerns expressed about "addiction to oil" and $3 per gallon gasoline, the marshalling of forces in this country to address the larger problem of global warming finally may have begun.