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By Roger Highfield on

Nature can help cool the planet – so long as we act now

As the Science Museum launches an exhibition about capturing climate-warming carbon dioxide, a new analysis shows investing in ecosystems could help cool the planet in the latter part of this century, but only if we act now. Science Director, Roger Highfield describes the new work, and a method to turn carbon dioxide into greener plastics.

The best way to curb harmful climate change is to cut the use of fossil fuels. Alongside that important transition, a range of technologies and nature-based methods to actively remove carbon are being studied, the subject of our new exhibition, Our Future Planet.

The most familiar way to capture carbon dioxide responsible for climate change is the tree, though nature has vastly more ways to do this, from wetlands to grasslands, and peat to kelp. However, there is still debate around how nature-based solutions can contribute to achieving our greenhouse gas emissions targets this century, notably to limit global warming to 1.5 or 2°C.

‘Until now there have been a lot of studies looking at the contribution of nature-based solutions to mitigating climate change, but over a range of timeframes, models, and quantified as emissions reductions rather than in terms of avoided warming’ said Dr Cécile Girardin of the University of Oxford’s biodiversity network. ‘Instead, we are looking at it in the context of temperature change, which is relevant to the Paris climate agreement that requires we limit warming to 1.5 to 2 degrees C.’

Dr Girardin, Prof Yadvinder Malhi, Prof Myles Allen (who recently appeared at our Manchester Science Festival) and colleagues studied an ambitious but realistic scenario that showed how by deploying large-scale conservation-based strategies, nature could absorb more carbon than the entire global transportation sector emits annually—some 10 gigatons of carbon per year.

They then modelled how this would affect global temperatures up to 2100 and, in the latest issue of the journal Nature, they report that nature-based solutions that manage, protect and restore ecosystems have a powerful role in reducing temperatures in the long term.

Forests and other ecosystems contribute long past the point of peak warming: in the 1.5°C scenario, which is modelled to peak by 2055, nature-based solutions could reduce temperatures by 0.4°C by 2100.

‘Crucially, which we hadn’t really seen before, in any of the models, we found nature-based solutions have an important role in cooling our global temperatures up until the end of the century,’ said Dr Girardin. ‘That is an important message: properly managed, these solutions could benefit many generations to come.’

She emphasised that they have to be the right solutions, not great monocultures that diminish biodiversity. ‘We need projects that are ecologically sound, that are socially equitable, that are designed to provide these benefits over a century or more.’

But the team also found the more ambitious the climate target, the shorter the timeframe for nature-based solutions: investment in ecosystems and land could play an important part in planetary cooling in the second half of this century and beyond only if we slash emissions and invest in ecologically and socially sound nature-based solutions now.

They argue that nature-based solutions must be scaled up rapidly ‘and not at the expense of other robust strategies’. By that they mean technological solutions, of the kind in the Our Future Planet exhibition.

‘We need to be pragmatic about this, the solution is uncompromisingly about decarbonising our economy. If we don’t keep the peak of global temperatures to 1.5 or 2 degrees, our goose is cooked and none of this matters’, said Dr Girardin.

In the second half of the exhibition, technological solutions are examined, such as mechanical trees to extract carbon dioxide, along with products made from carbon dioxide, spurred on by the inducement of an X prize, which range from making vodka to yoga mats.

The mechanical tree prototype for direct capture of carbon dioxide from the air, on display in Our Future Planet.
The mechanical tree prototype for direct capture of carbon dioxide from the air, on display in Our Future Planet.

I helped to judge the latest European Inventor Award and among the finalists are German chemists Christoph Gürtler and Walter Leitner who, with colleagues, pioneered a technique to use CO₂ as a building block for creating plastics, reducing energy usage and recycling waste CO₂.

Plastics manufacturing consumes 6-8% of worldwide oil production, contributing significantly to our overall carbon footprint. Polyurethanes – a class of polymers widely used in foams and plastics to make furniture, insulating material and so on – also need large amounts of crude oil for manufacture, rendering the process environmentally unsustainable.

In 2007, Gürtler and Leitner, working in a collaboration between RWTH Aachen University and Bayer MaterialScience (later renamed Covestro), studied how chemical catalysts, which trigger or speed up chemical reactions, can drive reactions between CO₂ and a crude oil derivative to make a chain-like molecule, known as a polyol, that can be used as a precursor for producing plastics.

Their patented technique helps cuts the fossil feedstock required to make the precursor by up to 20%. Cardyon – the CO₂-based product they developed – was commercialised and up to 5000 tonnes are being made at a pilot plant in Dormagen, Germany, using CO₂ from a nearby ammonia production facility.

Fifteen inventors or inventor teams from around the world have been nominated for this year’s Popular Prize of the European Inventor Award and you can vote for your favourite inventor.