Here's the equation, as it appears to me:
There are too many humans on the planet
All these humans are producing way too much CO2
All this CO2 is killing the environment. It's causing (or is going to cause) apocalyptic scenes that will make the Book of Revelation seem like a nursery rhyme. Lots of people will die.
One way to help the planet is to reduce the number of humans being born.
Less humans = smaller carbon footprint = happiness all around
[Except for those that were killed instead of being born, perhaps?
And if humans are such a disease, why don't we just kill off a few million? Selective culling you know. Or heck, wait till those apocalyptic scenarios come by and let those millions die? Smaller carbon footprints will result from that, right? We can just hike up to the Rockies, and continue to buy indulgences, umm, carbon offsets.]
Yesterday, the Holy Father gave a talk where he highlighted the need to protect the environment, including reducing greenhouse gas emissions.
I somehow doubt that he'd advocate the family planning measures, including abortion, that the Sierra Club is now promoting.
"Human intelligence has many possibilities for stimulating a new, lasting development." That is absolutely true. And one can and should work towards finding ways to continue development -- economic growth primarily and integration into the global economy, the one time-tried mechanism that has actually brought hundreds of millions out of poverty in the past century -- in a manner that also doesn't destroy the environment.
[Some quotes from a leader in the Economist back in Nov. 2005 --
FREDERIC BASTIAT, who was that rarest of creatures, a French free-market economist, wrote to this newspaper in 1846 to express a noble and romantic hope: "May all the nations soon throw down the barriers which separate them." Those words were echoed 125 years later by the call of John Lennon, who was not an economist but a rather successful global capitalist, to "imagine there's no countries". As he said in his 1971 song, it isn't hard to do. But despite the spectacular rise in living standards that has occurred as barriers between nations have fallen, and despite the resulting escape from poverty by hundreds of millions of people in those places that have joined the world economy, it is still hard to convince publics and politicians of the merits of openness. Now, once again, a queue is forming to denounce openness—ie, globalisation. It is putting at risk the next big advance in trade liberalisation and the next big reduction in poverty in the developing countries. ...I'm rambling now, but I am also reminded of a thought-provoking monograph written by Thomas Sowell called "The Quest for Cosmic Justice." His contention is that a "God's-eye-view" conception of justice is simply not available to us, and once we start thinking like utopians, the results for us, who do not see as God does, are disastrous.
Although the case for reducing poverty by sending more aid to the poorest countries has some merit, the experience of China, South Korea, Chile and India shows that the much better and more powerful way to deal with poverty is to use the solution that worked in the past in America, western Europe and Japan: open, trading economies, exploiting the full infrastructure of capitalism (including financial services—see our survey on microfinance) amid a rule of law provided by government. In other words, globalisation. To paraphrase Samuel Johnson, anyone who is tired of that is tired of life.
How this relates to traditional Catholic social teaching, I'm not entirely sure, perhaps because I'm woefully uninformed about the content of that social teaching. That's an ongoing project -- how to reconcile what I've learned about the virtues of market economics, capitalism, free trade and globalization, with what the Church's social teaching actually posts (versus, what one hears being claimed on its behalf).]