Our ancestors lived in eras we call the Stone Age, the Bronze Age and the Iron Age. Ours is the “fossil-fuel age”. The energy we have extracted from the Earth’s reserves of fossilised sunlight has spread (unequally shared) abundance across humanity. Will this continue? Can we manage its impact on our environment? The answers will shape the future of our complex global civilisation.

As always, BP’s energy outlook provides a glimpse into a possible future. No doubt, its forecasts will be wrong. But it tells us what well-informed people at the heart of the oil and gas industry consider “the likely path of global energy markets to 2035”. It puts forward five important propositions about a plausible energy future.

First, global economic output is forecast to rise by 115 per cent by 2035. Asian emerging economies – principally China and India – are expected to generate more than 60 per cent of that increase.

The primary driver of the rise in global output is expected to be a 75 per cent jump in global average real output per head, as the prosperity of emerging economies catches up with that of high-income countries. Population growth plays a distinctly subsidiary role. It is not the number of people, but rather their prosperity, that drives demand for commercial energy.

Second, as a result of rapidly rising energy efficiency, energy consumption is forecast to grow by only 37 per cent. This is far less than the rise in output of real goods and services.

Third, emissions of carbon dioxide are forecast to grow by 25 per cent, a growth rate of about 1 per cent a year. In terms of the link between output and emissions, this is a huge achievement. But – given the need to cut emissions outright, in order to have a good chance of limiting the global average temperature rise to below 2C – it is wholly inadequate. Thus, in 2035, emissions of CO2 are forecast to be 18 billion tonnes above levels suggested by the International Energy Agency’s “450 Scenario”. This seeks to limit atmospheric greenhouse gas concentration to the equivalent of about 450 parts per million of CO2. If such targets are to be met, something far more radical needs to occur.

Fourth, improvements in energy efficiency are a far more important driver of the relatively low growth in emissions than shifts in the fuel mix. This is despite a substantial rise in use of renewables. So, between 2013 and 2035, output of renewable energy is forecast to grow by 320 per cent. Even so, its share in primary energy production is forecast to grow only from 2.6 per cent to 6.7 per cent.

The combined share of renewables, hydroelectricity and nuclear power grows only from 9 per cent to 19 per cent. This, then, is expected to remain a fossil-fuel age.

Fifth, the revolution in the production of shale gas and tight oil is expected to continue, with their share in primary energy production rising to about 10 per cent.

An important result is large shifts in patterns of trade. So the US is forecast to shift from being a net importer of 12 million barrels a day of oil in 2005 to being a net exporter by 2035. Meanwhile, China is forecast to shift to being a net importer of more than 13 million b/d by 2035 (from self-sufficiency in the early 2000s); and India to being a net importer of about 7 million b/d. Such shifts have huge geopolitical implications.

It would be wrong to describe these forecasts as simply “business as usual”. They actually imply a faster rise in energy efficiency than between 2000 and 2013. But they are not radical. The world would continue to rely overwhelmingly on fossil fuels and it would emit ever greater quantities of greenhouse gases. Could we do better?

I start from the presumption that humanity will aspire to and often manage to achieve the prosperity now taken for granted in rich countries. So we need an accelerated technological revolution. At the Oslo Energy Forum last month, I heard Amory Lovins of the Rocky Mountain Institute describe just such a revolution. He argued, for example, that US gross domestic product in 2050 could be 2.5 times what it is today, even if the country stopped using oil, coal and nuclear energy altogether and cut its use of natural gas by one-third. This would mean carbon emissions of just one-fifth of their present level.

Moreover, he argued, the revolution could well be driven by market forces alone, given the growing economic superiority of the new technologies. There might, he suggests, be no need to to take direct policy action against rising emissions of carbon dioxide.

The sense of the BP report (not surprisingly, perhaps, given that BP is a fossil-fuel producer) is that such a radical and rapid market-driven revolution is unlikely. The purported obstacles are many: costs, technological limits, slow turnover of the capital stock, inability to implement policy globally and natural inertia. In brief, I fear BP is right about the obstacles.

But Mr Lovins might be right about the opportunities, though only if policy makers give them a big push.

If governments could agree to implement a tax on carbon, they would give a big impulse towards an energy future that is more efficient and less polluting. Governments should invest strongly in fundamental science and new technologies. Finally, governments can help the spread of new technologies abroad and help finance their uptake at home. With this push, normal market forces should pull the world economy towards a more sustainable future.

Mass poverty is not an option. But neither is taking ever-bigger gambles with the climate. The right course has to lie in between. To put ourselves on that course, we need to wean ourselves off the excesses of the fossil-fuel age. It is a daunting challenge. But it has to be met, for our children’s sake.