Columnist: Much of North America and western Europe is more heavily forested and has less acid rain and better air quality now than five decades ago.
Conclusion
Maybe those people saying, we're not in imminent ecological doom, and if we're too stringent with environmental regulations, we might lose the revenue that pays for these preservation programs are correct.
Evidence
Much of North America and western Europe is better forested and has less acid rain now, compared to five decades ago.
Evaluate
This has a very loose argument structure, so I would assume we can treat it pretty conversationally. Just picture the age old debate about the environment.
the Left: by 2050 Earth will be unlivable if we don't immediately take drastic measures!
the Right: c'mon, you've been prophesying imminent doom forever and things aren't as bad as you thought. plus, if we take drastic measures, we'll mess up the economy, and the economy is what's currently able to pay for the environmental initiatives
The author is saying that the recent successes we're seeing (two continents have more forest and less acid rain than before) is support for the people on the Right.
Goal
Look for something that helps the Right — the environment is not on the brink of doom / the environmental victories we've achieved over the last five decades were paid for with natural resource wealth (i.e. oil money) / were we to restrict use of natural resources, it could lead to less funding for future environmental initiatives.