Welcome to the Battle of the Summits. On Tuesday we had UN Secretary General Ban Ki-moon’s Climate Change Summit in New York at which the presidents of the world’s two biggest polluters, China and the US, tried to convince delegates that they were serious about tackling carbon dioxide emissions.

Today the G20 opens its two-day summit in Pittsburgh, where the transition to a low carbon economy will receive lip service alongside the main preoccupation: returning the world to economic growth. If it comes down to a policy battle between growth and climate, the “grow-at-all-costs” lobby will probably win.

By coincidence, this week has also seen the forecast that the recession has produced the biggest annual fall (2%) in carbon emissions in 40 years and the prediction that the UK economy will emerge from recession in the current quarter and continue to grow into next year.

For years, like children who are too young to be told a terrible truth, we’ve been sold the myth that we can have our cake and eat it.

Nicholas Stern’s comprehensive analysis of the economics of climate change claimed we could combat climate change and continue to enjoy economic growth, provided we made minor sacrifices now. Al Gore (and Alex Salmond) have tried to tell us that combating global warming will be “good for business”, with a “green jobs bonanza”. David Cameron gave us “realistic environmentalism”: “not green or growth but both”.

Various environmentalists have tried to convince us that the green transition is going to be fun. Yet all the while carbon emissions have risen, until a global recession interrupted the world’s insatiable appetite for coal, steel and concrete.

Two years ago George Monbiot was brave enough to utter a heresy a lot of us had been thinking. “I hope that the recession being forecast by some economists materialises,” he said.

Though it would generate hardship, unemployment and business failures, it might just buy the world enough time to adopt low carbon strategies before catastrophic and irreversible climate change is triggered by rising emissions.

Yet our prime minister’s first instinct was to rush off to OPEC in the hope of increasing the flow of oil, bringing prices down and returning quickly to growth. Brown’s core

philosophy has always involved the marrying of economic growth to social justice. The more limited Tory version talks of “sharing the proceeds of growth”. Politicians use growth and the hope it engenders as a substitute for tackling inequality. It’s a lot easier than redistribution.

Economic growth is in our genes. The desire to acquire as much as we can is part of our survival instinct. Economic growth has given us decent homes, flushing toilets, libraries, parks, better health and enough to eat. Today the residents of China, India, Afghanistan and Ethiopia need economic growth but do we? Is anyone in Scotland starving or shoeless?

As more of us moved from poverty to affluence, the rich have had to differentiate themselves with ever more ludicrous purchases. The last time I was in the US, personalised mini submarines were the season’s “must have” for those with more money than sense.

We have become compulsive consumers. In the 10 years since our family moved to our current house, we have filled the entire loft with our surplus guff, while my Ethiopian friends could fit their entire worldly goods in the boot of a small car. Isn’t it time the rich world concentrated on redistribution, rather than growth?

The recession gives us a window of opportunity. It has had a contradictory impact on the climate change agenda. The bad news is that faltering economies deterred risk-averse

investors from supporting clean energy projects. The good news is that slowing demand used up fewer resources and generated fewer emissions. The fly in the ointment is debt, which makes everything harder. It risks swallowing the money for the green new deal and it increases the pressure to resume economic growth.

We should not kid ourselves that everlasting growth can be achieved without catastrophic rises in emissions. This week Willie Walsh of British Airways has been telling us the aviation industry can halve its emissions by 2050. Don’t believe him.

The lesson from the car industry is that voluntary action is not enough and growth in travel swamps gains from improved energy efficiency. The only answer is to tax aviation fuel to make fliers pay the environmental as well as the economic cost of their trip.

In New York on Tuesday President Hu Jintao promised China would curb rises in emissions, but they need to be falling by 2020.

Barack Obama talked of reducing US emissions by what amounts to a few per cent by that date. It needs to be 40%. It’s time to ask whether the developed world can continue with growth at the same time as

effectively tackling climate change. Are politicians capable of thinking the unthinkable on this issue?

Also we need to admit that it’s going to hurt. We don’t need to return to the Stone Age but we do need to accept that the low carbon revolution will mean rationing, regulation and austerity.

Our grandchildren’s lives may look more like the 1950s than the 1990s. Is this bad? As Professor Kevin Anderson of the Tyndall Centre asked: “Has the tripling of our economic wherewithal since the 1950s brought about the tripling in our sense of well-being, do we really gain significant welfare benefit from our daily access to mange tout, and are carbon

emissions, noise and physical division of communities by busy roads

adequately compensated by our easy access to private transport?”

Ed Miliband is right to be haunted by the possibility that politicians will fail to reach an agreement on climate change in Copenhagen in December. Since Stern, there is no serious argument now about the science of climate change but there is still an argument about the ethics of asking people to make sacrifices now in the interests of future generations. In my book this is not a choice between our generation and our descendents, but the likelihood that if we do not act now we will not have any descendents.

As Kevin Anderson put it rather chillingly this week: “At the moment the economy is trumping the environment. Ultimately the environment will always trump the economy.”