Scientists and Politicians Must Rally to Tackle Climate Change

by Martin Rees*

Throughout past centuries, we have been vulnerable to natural threats, such as earthquakes and volcanic eruptions. But there is one reassuring thing about such threats: their annual probability is not changing much — it was much the same for the Neanderthals more than 40,000 years ago.

By contrast, we are now deep into the Anthropocene — the period in which human activities can ravage the earth’s ecosystems. The pressures of a growing human population and economy, on land and on water, are already high. Humans appropriate a growing fraction of the world’s biomass, with drastic ecological consequences. Extinction rates of plants and animals are rising. If too much fossil fuel is burnt in coming decades the rise in the amount of carbon dioxide in the atmosphere could trigger irreversible long-term changes. These are the issues that demand our attention ahead of the UN conference in Paris in December that will seek a global agreement on climate change.

When scientists investigate facts, they must be as objective as possible. But when they debate the economic, social and ethical aspects of any issue, they speak as concerned citizens and not as experts. There are indeed real uncertainties in climate science. But present disagreements about climate policy stem less from differences about the science than from different ethical stances — in particular, in the degree of obligation we should feel towards future generations.

Those who assess the impact of climate change by applying a standard discount rate to estimates of future costs are in effect writing off whatever happens beyond 2050. Scientists would agree that there is indeed little risk of catastrophe within that time-horizon, so unsurprisingly such analysis concludes that tackling climate change deserves a low priority compared with other public policy aims. But the grandchildren of today’s young adults could live through several decades of the 22nd century. Anyone who cares about those generations will deem it worth making an investment now to protect them from the worst-case scenarios.

Suppose astronomers had tracked an asteroid and calculated that it would hit Earth in 2080, 65 years from now — not with certainty, but with, say, 10 per cent probability. Would we relax, seeing it as a problem to be set on one side for 50 years? I do not think we would. There would surely be a consensus that we do our damnedest to find ways to deflect it, or to mitigate its effects. By contrast, our governments respond with torpor to the climate threat, as concerns about future generations slip down the agenda.

The task of weaning the world away from dependence on fossil fuels is indeed daunting. Renewable energy is expensive to generate. Power from the sun and wind is intermittent. Fortunately, technology in solar energy and batteries is proceeding apace — but needs to accelerate further.

When the Americans embarked on the Apollo project to land people on the moon, they succeeded within a decade because they devoted huge resources to it. We need a similar big commitment to generate and store clean energy, bringing down its costs. Unlike the original Apollo programme (which was fuelled by superpower rivalry with the Soviet Union) this should be a co-operative venture where all major countries step up their efforts.

Research on energy is currently on a far smaller scale than medical research — but it is just as crucial for the world. The faster it proceeds, the sooner will the power from renewables become as cheap as coal-fired power stations.

It would also be far better if clean energy could be made affordable to less developed countries before they invest in more generating capacity. Such countries — and the people who have contributed the least to climate change — stand to lose the most because of it.

Heat stress will most hurt those without air conditioning, crop failure will most affect those who already struggle to afford food, extreme weather events will most endanger those whose homes are fragile. Another ethical issue concerns the non-human environment. Climate change is aggravating a collapse in biodiversity that could eventually be comparable to the five mass extinction events in Earth’s history. We are destroying the book of life before we have read it. To quote the great ecologist EO Wilson, if our despoliation of nature causes mass extinctions, "it is the action that future generations will least forgive us for”.

To design wise policies, we need all the efforts of scientists, economists and technologists, and the best knowledge that the 21st century can offer. But to implement them successfully, we need the full commitment of political leaders and the full support of the voting public. As Pope Francis’s Encyclical on environmental issues proclaims, our responsibility — to our children, to the poorest, to steward the diversity and richness of life on earth — surely demands nothing less.

*The writer is the Astronomer Royal

(Financial Times)