My hiking companion and I have lost our way on this damp late-summer morning. We're on a treeless, mist-shrouded hilltop in Snowdonia National Park, 1,000 feet or so above the Irish Sea along the coast of northern Wales. The bleating of sheep drifts up from the slopes below, muffled by fog that hides the lay of the land. We're trying to reach a village called -- by those able to pronounce its name -- Abergynolwyn, which lies in a nearby valley. But with the murk, we can't find the way down. Sir John Houghton pulls a topographic map and a compass from his backpack. After a few moments of thought he says, "We want to head north. That should take us downhill." So we follow a sheep trail, and a bit later I watch Houghton, who is 76, nimbly hoist himself over a chest-high wire fence.
Charting a path through difficult terrain is nothing new for Houghton, who may be the most important scientist you've never heard of. From 1988 until his semi-retirement in 2002, he was one of the leaders of the Intergovernmental Panel on Climate Change (IPCC), a body created by the United Nations 20 years ago to study global warming. As cochairman of the IPCC's scientific working group, Houghton had to coordinate the efforts -- and cope with the egos -- of more than 2,000 scientists from dozens of countries. Against all odds, the IPCC, which could have been a fractious and unwieldy international boondoggle, produced a series of authoritative and scientifically rigorous reports firmly establishing the magnitude of the threat posed by climate change. Largely because of the efforts of Houghton's group, the IPCC shared the 2007 Nobel Peace Prize with Al Gore.
Houghton has been at the forefront of climate research for decades. He started investigating global warming more than 40 years ago, after joining the department of atmospheric physics at Oxford University. From 1983 until 1991 he was the head of the Met (short for Meteorological) Office, the United Kingdom's national weather service. He served as chairman of the Royal Commission on Environmental Pollution for much of the 1990s. However, the affiliation that means most to him is one rarely associated with a serious commitment to science or environmental activism. Houghton is a devout evangelical Christian.
"I'm constantly asking myself, why on earth should I believe in Christianity? Do I really believe it?" he says to me, discussing his faith while we pause for lunch beside a logging road. "It seems so impossible to believe in. But then I ask, can I not believe it?"
Houghton's faith is central to his response to the hard, inescapable reality of global warming. He believes we can still save the world from the worst effects of climate change, but he is also very specific about how little time we have left -- seven years. Despite the imminence of calamity, he remains hopeful that we will overcome the threat -- if the developed world recognizes that global warming is as much a moral and spiritual problem as an environmental one.
I first met Houghton at a talk he gave at Cambridge University earlier in the summer. He is a slender, elegant man, with a hawklike profile, deep-set blue eyes, and thinning white hair. He devoted the first half of his talk entirely to the science of global warming, arguing that we are already seeing its first effects in events like the heat wave that struck central Europe in 2003 and is estimated to have caused more than 20,000 premature deaths.
Then Houghton changed gears. The talk became intensely personal, a profession of his Christian faith. He called global warming "a weapon of mass destruction" and said that the rich nations of the world, which have generated most of the greenhouse gases, have a moral obligation to solve the problem. "We're generally good at sharing in families, communities, and nationally, but not so good globally," he said. "If the Old Testament prophets were here, they'd be tearing their hair out, cursing us, telling us we're absolutely greedy, and they'd be right."
The frank discussion of faith from such an eminent scientist surprised me, and I asked Houghton if I could speak with him at more length. He invited me to spend a couple of days at his home in Aberdovey.