HERE we are, in 2020, at the start of not just a new year but a new decade. It is one that could prove make-or-break for the dominant challenge of the 21st century: climate change. Will it be a decade of delivery or a decade of disaster?

There was an ominous portent at the start of the week, when the authorities of Australia declared that it was now too late for residents in the state of Victoria to evacuate their homes in the face of advancing wildfires. Let’s hope that we haven’t also left it too late to act on climate change.

The Today programme on Radio 4 has guest editors between Christmas and New Year. With characteristic BBC balance — the approach which brought it accusations of bias from almost all political factions during the recent general election — it addressed global warming by inviting the arch-conservative Charles Moore and the climate activist Greta Thunberg to edit back-to-back editions of the programme.

The comparison was instructive. Mr Moore’s contributors included Professor Michael Kelly, a trustee of the Global Warming Policy Foundation, which states that climate science is “not yet settled”. Dr Kelly, who is a professor of electronics, proclaimed himself optimistic that everything would be sorted out by a decline in world population.

He was supported by Lord Ridley, the former science writer of The Daily Telegraph, who draws a considerable income from open-cast coal-mining and who was chairman of Northern Rock when the bank collapsed owing the British Government £26.9 billion. Our “overreaction” to climate change risks “shutting down civilisation”, he declared, smearing the BBC’s environment editor en passant. He also spent a good proportion of his time on BBC radio complaining that climate sceptics like him were not allowed on the BBC.

In contrast, Greta Thunberg’s programme took its science from Kevin Anderson, who is Professor of Energy and Climate Change at Manchester University and a former director of the Tyndall Centre for Climate Change Research, and author of more than 100 academic papers on the subject.

Professor Anderson declared that, having ignored 30 years of warnings, we now have little chance of maintaining the rise in global temperature to below two degrees Centigrade. The resultant fires, floods, windstorms, and droughts are already having a disastrous impact on the world’s poorest people. Indeed, unless we radically reframe our behaviour and the structure of our economy, temperatures could rise to four degrees Centigrade by the end of this century, “which will be like living on another planet”.

So, what is the way forward? The director of new energies at Shell, Maarten Wetselaar, outlined its $2-billion plan to transition from fossil-fuels to low-carbon energy. Yet it is still spending $25 billion on oil prospecting.

The world of finance, which holds large amounts of oil-company shares, must exert pressure for that to change. The trouble, says the outgoing governor of the Bank of England, Mark Carney, is that financial firms are “not moving fast enough” away from fossil-fuel investments. Many of those investments, which could rapidly become worthless, are lodged in the pension funds of ordinary people. Perhaps it is time for us to demand that our pension funds move our investments elsewhere.