TAIPEI, Taiwan

I have seen the future, and it won’t work.

These should be hopeful times for environmentalists. Junk science no longer rules in Washington. President Obama has spoken forcefully about the need to take action on climate change; the people I talk to are increasingly optimistic that Congress will soon establish a cap-and-trade system that limits emissions of greenhouse gases, with the limits growing steadily tighter over time. And once America acts, we can expect much of the world to follow our lead.

But that still leaves the problem of China, where I have been for most of the last week.

Like every visitor to China, I was awed by the scale of the country’s development. Even the annoying aspects  much of my time was spent viewing the Great Wall of Traffic  are byproducts of the nation’s economic success.

But China cannot continue along its current path because the planet can’t handle the strain.

The scientific consensus on prospects for global warming has become much more pessimistic over the last few years. Indeed, the latest projections from reputable climate scientists border on the apocalyptic. Why? Because the rate at which greenhouse gas emissions are rising is matching or exceeding the worst-case scenarios.

And the growth of emissions from China  already the world’s largest producer of carbon dioxide  is one main reason for this new pessimism.