The Big Idea We Need To Reverse Climate Change Not Just Stop It Science And Nature Books

Another reason to be optimistic is that clean energy has gotten cheaper much faster than expected. The cost of both solar and batteries has fallen tenfold in the last 10 years, and the cost of wind power by two-thirds. Solar power is the cheapest form of new electricity manufactured in much of the world today, and electric vehicles now account for 13% of new vehicle sales worldwide. But that doesn’t mean we can rest on our laurels. Far from it. We are still nowhere near where we need to be to meet our climate goals. In the most recent Intergovernmental Panel on Climate Change (IPCC) report, which I contributed to, we found that if we want to limit warming to 1.5C, we can only emit 420 billion tonnes of CO2 – equal to about 10 years of current emissions. This means that even with the progress we have made, the rise in global temperatures is very likely to exceed 1.5C in the early 2030s. So where does that leave us? The short answer is: “It’s complicated.” First, it is important to emphasize that climate change occurs gradually and not in big jumps. There is no evidence that 1.5 C represents a threshold between manageable and catastrophic impacts. But the more we push the climate beyond what it has been for the last million years, the greater and more unpredictable the risks become. Earth’s past major climate changes and possible future tipping points, such as the release of CO2 from thawing permafrost, should give us pause: we cannot easily predict what might happen. Every tenth of a degree matters if we want to minimize the harm we cause ourselves and leave to future generations. But equally, just because we’re passing 1.5C doesn’t mean there’s no way back. We know that if we can reduce emissions to zero, the world will essentially stop warming. And climate models show that if we remove more CO2 from the atmosphere than we emit, it will actually cool the world. Removing CO2 from the atmosphere and oceans was highlighted in the recent IPCC report as “essential” to meeting our climate goals. Almost all climate models suggest we need to remove 6 billion tonnes of CO2 per year by 2050 alongside rapid emissions reductions to bring temperatures back to 1.5C by the end of the century. Every tenth of a degree matters if we want to minimize damage A form of carbon dioxide removal that humans are already familiar with comes in the form of trees and soil. Earth’s living systems already sequester about a quarter of the CO2 we emit today (with another quarter absorbed by the oceans). There is real potential to enhance this ‘natural carbon sink’ by protecting forests, planting more of them and changing the way we manage farmland and pasture to get more carbon into the soil. This is a relatively low cost today, but it is also likely to prove temporary. Trees can be felled, burned or killed by beetle infestations, while soil can dry out due to drought or heat – and these risks will increase as a result of climate change. There are also limits to the land available for use. Overall, the models suggest that trees and soil could only provide half of the carbon dioxide removal we need. There are other more reliable ways to remove carbon from the atmosphere in the long term. Such approaches are still in their infancy, but are being rapidly deployed by hundreds of companies around the world. They include direct air capture, which sucks CO2 directly from the atmosphere. taking agricultural waste or wood and storing carbon from it deep in the ground. spreading minerals such as basalt that absorb CO2 from the atmosphere on agricultural fields. removal of CO2 directly from ocean water. making ocean water less acidic so it can absorb more CO2. and sinking algae or other plants into the deep ocean where the carbon they have absorbed will remain for millennia to come. These approaches are less likely to backfire and are less limited by available land. But they tend to be much more expensive, at least right now. Therefore, we should focus on making them cheaper, as we did with renewables. That’s the goal of Frontier, a $925 million upfront purchase commitment that Stripe, where I head climate research, has launched with Alphabet, Shopify, Meta and McKinsey. The idea is simple: by guaranteeing money upfront, we send a message to entrepreneurs and researchers that if they build and scale these early-stage technologies, we’ll buy them. This approach was piloted a decade ago to accelerate the development of pneumococcal vaccines in low-income countries and has saved an estimated 700,000 lives. We have a saying in the world of climate science – that CO2 is forever. It will take nearly half a million years for one ton of CO2 emitted today from burning fossil fuels to be completely removed from the atmosphere naturally. This means that when we try to offset or reverse fossil fuel emissions – for example, with carbon offsets – these interventions should work on a similar timescale: one ton of emissions from cutting down trees can be offset by adding more carbon to trees or soils. but CO2 from fossil fuels must be balanced by more permanent carbon removal. That’s why the respected Science Based Targets initiative allows only measures that permanently remove carbon from the atmosphere to offset a company’s remaining fossil fuel emissions to the net zero standard – and only alongside deep emissions reductions. The role of carbon removal should not be overestimated. It is often cheaper to reduce emissions than to remove CO2 from the atmosphere after the fact. Models that limit warming to 1.5C show that we need to reduce global CO2 emissions by about 90%, while only using carbon removal for about 10%. But 10% of the solution to a problem as big as climate change is still something we can’t ignore. In 2021 the world spent a total of 755 billion dollars. In 2021 the world spent a total of $755 billion to reduce emissions. We should probably aim to spend about 1% of that money on carbon removal technologies. But we can’t just sit back and assume that ways to remove billions of tons of CO2 a year will magically appear in the coming decades. By investing today, we can ensure we are well positioned to make net zero a reality, stop the world from continuing to warm, and give ourselves the tools to finally reverse global warming in the future.

Further reading#

Further reading