People versus Nature threat

Cath O’Driscoll

AAAS President Claire Fraser kicked off the 2021 virtual meeting with a quote from Winston Churchill: ‘Never let a good crisis go to waste.’

‘History has shown that disaster can often be the time of biggest change,’ Fraser noted. While praising the efforts of scientists in response to the Covid-19 crisis, she highlighted the damage of growing population density on Nature’s ‘dynamic ecosystems’ and warned of the threats to human health and well-being.

There are an estimated 1tn microbial species on earth and an estimated 1031 viruses, one for every star in the universe a hundred million times over, Fraser pointed out, referring to a 2009 US NAS report that suggested 65% of recent disease outbreaks had a zoonotic origin. Mammals and birds host 1.7m novel viruses and, while most ‘spill-over events’ to people are harmless, increased travel, urbanisation and deforestation are all driving up the risks of yet more infections such as Covid, rabies and Lyme disease.

‘With so many potential zoonotic diseases, our proximity to wildlife puts us in harm’s way,’ Fraser remarked, adding that global population is estimated to hit 11bn people by 2100.

Already, since the 1960s, global milk production has doubled and meat production trebled, while egg production has risen four-fold. Agriculture currently accounts for 26% of greenhouse gas emissions, 70% of freshwater withdrawals and 78% of global ocean and freshwater pollution. Meanwhile, a staggering 94% of Earth’s mammal biomass, excluding humans, is livestock.

‘Livestock outweighs wild mammals by a factor of 15:1,’ she said.

A 2020 Science paper pointed out that the planet has lost around half of all organisms and a quarter of tropical rainforest in the past 50 years. Yet more evidence, Fraser continued, that ‘together we’ve entered into the world’s sixth major extinction event’.

One consequence of the Covid-19 pandemic was to reduce global manufacturing output and transport, she added, yet this cut of 1.6bn t of CO₂ emissions is only 5% of global output and is already seeing reversal as the world recovers. To limit global warming to the 1.5°C rise in temperatures targeted in the Paris agreement would need a reduction similar to that caused by the pandemic every year for the next decade and beyond, scientists have estimated.

Unlike Covid-19, climate change and other pressing global challenges and threats do not inspire the same urgency among politicians and the public. What the Covid pandemic showed was that countries that acted early – Japan, South Korea, New Zealand and Australia – fared far better in terms of numbers of cases, Fraser said. In the US, had restrictions been imposed just two weeks earlier, there could have been an estimated 1m less cases and 59,000 fewer deaths.

Climate change operates on a very different timescale to Covid. But Fraser warned that delays in repositioning our economy will be very costly.

‘We as scientists have been losing the battle against a growing antiscience movement in this country for too long,’ she said, pointing to the AAAS Science Engage initiative to facilitate dialogue with the public.

The world shouldn’t wait for the next crisis to arrive, she warned. ‘As Covid has demonstrated, we live in an interconnected world. We must move away from denial and towards greater global cooperation where countries are aligned on shared fundamental goals.’