It takes 1.5km to brake a coal train to a standstill and nearly 9km to stop an oil supertanker.
BP's Statistical Review of World Energy, released last week, shows the world's energy economy has a similar inertia.
Despite demands for rapid transformation for the sake of the environment, the global complex of mines, wells, pipelines, wind farms, nuclear plants, power lines and petrol stations changes very slowly.
Nor is it changing in the right direction - 2010 was the hottest year on record; last year the 10th hottest, despite cooling currents in the Pacific. The Arctic ice shrank to the smallest volume ever. While the ice melts, changes in our energy economy are moving at a glacial place.
To slow the progress of global warming, carbon-dioxide emissions need to fall. Instead, they rose by 3 per cent; for all our environmental policies, emissions have dropped only in years of global recession.
Higher emissions were driven by coal, whose use was up a remarkable 5.3 per cent last year. In the energy world, that is rapid change - but in the wrong direction. Often thought of as a 19th-century fuel, coal's resurgence is, led, not surprisingly, by China. The Chinese now burn half of the world's coal.
Not since 1965 has coal use exceeded oil, but at this rate, King Coal could be again ahead of Big Oil within three years. That is not good news for the Arabian Gulf: oil producers here are enjoying high prices, but at the cost of losing their market.
For all the supposed success of renewable energy - solar and wind power - in Germany, Spain, Italy and Portugal, their coal use, too, went up sharply. With its energy policy driven by whim and political pandering, Germany's famed solar-power programme, in a country as sunny as Alaska, was outweighed by shutdown of its nuclear plants.
There are some bright spots. Subsidies for oil consumption fell sharply. Driven by the shale revolution, relatively clean gas continued to gain ground on coal in the United States. And renewable energy has now tripled its share in a decade. Still, its tiny share of 2.1 per cent shows how long it takes for new technologies to replace the vast installed base.
What can shift the momentum of this juggernaut, which is taking us into increasingly dangerous territory?
At the moment, the default policy setting is a messy tangle of issues such as those being discussed at this week's Earth Summit in Rio de Janeiro. Barack Obama's administration in the US seems to have given up talking about climate change, while taking piecemeal action via regulation of coal power stations and car mileage. Despite progress in some areas, the coal trains in China and India and the Hummers in the Middle East rush on unstoppably.
The 18th United Nations climate conference is approaching in Doha in November, but it seems increasingly clear that global governance is simply not capable of delivering a comprehensive deal to limit emissions.
Dramatic advances in technology might shift the balance. Solar and wind power are now competitive with fossil fuels, in the right conditions. And the real energy revolution of the past decade, gas and oil from shales, continues to gain pace: the US was the fastest-growing non-Opec oil producer last year.
But new energy technologies take years to commercialise, and it is rare for fossil-fuel plants, with lifetimes of 30 to 50 years or more, to be decommissioned prematurely.
With sudden transformations of the energy system unlikely, the most optimistic outcome for next year's BP Review seems to be that gas and renewables will halt and then reverse coal's gains. And the climate, which responds even more slowly and inexorably, will go on heating up.
Robin Mills is the head of consulting at Manaar Energy, and the author of The Myth of the Oil Crisis and Capturing Carbon
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