In July, in the wake of extensive flooding in Northern England, a statement was issued by Graham Dow, the evangelical bishop of Carlisle. He called the floods "a strong and definite judgment because the world has been arrogant in going its own way." The bishop, remarkably, was laying blame for the floods on recent legislation that extended to gay couples the right to a civil marriage. His pronouncement met with more astonishment than anger in this secular nation, but it is a reminder that, since Biblical times, human beings have held themselves responsible for natural disasters. Only recently have scientific advances allowed us to interpret earthquakes, storms and floods as random events, the product of blind geological and meteorological forces.

But one does not have to subscribe to the bishop's superstitions to see that the line between natural and man-made disasters is less clear-cut than one might think. And that is a lesson we will have to learn, as our way of life takes an ever-greater toll on the environment.

This summer's floods have not been unprecedented. Britain has experienced comparable flooding in the past, for instance, after the heavy winter of 1947. But this year there has been much discussion of whether the floods have been caused, or worsened, by human agency. Is the increasing frequency of extreme weather conditions a phenomenon deriving from man-made climate change? Certainly, scientists have linked the growing number of typhoons in tropical latitudes with rising sea temperatures, which are a consequence of global warming.

As it happens, in the case of these floods, such a link seems unlikely. Meteorologists have generally predicted that climate change is likely to bring drier summers and wetter winters to the British Isles. This season's heavy rain is probably a fluke. Still, the melodrama of individual disasters may obscure the bigger picture. This June, the wettest in living memory, was nevertheless hotter than average, as has been every month this year and last.

Nor is global warming the only way in which human activity has the potential to exacerbate the impact of natural disasters. The floods have thrown into relief the fact that the comfortable lifestyles we now enjoy may not be ecologically sustainable. Responding to a shortage of affordable housing, British Prime Minister Gordon Brown has announced new targets for building: 240,000 houses are to be built annually. But the summer's events have called this popular policy into question. First, most of these new houses will have to be built on vulnerable flood plains. Worse than this, widespread building is likely to trigger a vicious circle. Tarmac and paving stone are less porous than soil, so urbanization is itself likely to trigger further flooding.

This contradiction is relevant across the developed world. Japan, like Britain, has suffered a natural disaster this summer. On July 16, an earthquake centred off the coast of Niigata Prefecture killed 11 people and injured more than a thousand. To use insurance company parlance, this was indeed an "act of God." But Japan narrowly escaped an even greater, man-made disaster. The quake caused a leak at a nuclear power plant in Kashiwagi, Niigata Prefecture, spilling 1,200 liters of water contaminated with radioactive substances into the Sea of Japan. The scale of the contamination remains unclear; what is clear is the danger of relying on nuclear power in an earthquake zone. Were an earthquake to disrupt a working reactor's cooling systems, an uncontrolled chain reaction could lead to a nuclear explosion. Yet Japan, chronically short of resources, is tied to nuclear energy. If it is to sustain its prosperity, it has no alternative but to risk a possible catastrophe.

The nub of the matter is this. The developed world is wedded to lifestyles that involve the exorbitant exploitation of resources and the disruption of a balanced ecological system. As a consequence, we are literally reaping the whirlwind. I began this article by criticizing a senior churchman. But we might heed the words of his colleague, Richard Chartres, bishop of London: "We are all part of the problem and part of the solution. Instead of living as if we owned the Earth, we need to recover a sense of being participants in a web of life with responsibilities to other life forms and to our children."

Alexander Jacoby is a British film critic and writer who lived in Japan from 2002 to 2005. He is currently writing a handbook of Japanese film directors and pursuing doctoral studies.