The Intergovernmental Panel on Climate Change (IPCC) completed its 6th Assessment Report in March, 2023 (IPCC AR6). Its findings are sobering. Climate-related risks have increased since the previous report, with estimated long-term impacts much more severe than those extreme weather events that are grabbing headlines today. With every increase in global heating, losses and damages will accelerate and compound risks that will become more complex and difficult to manage. The IPCC AR6 provides a detailed account of the worryingly negative impacts of our current projected warming pathway of 2.5 degrees C, casting doubt on the capacity of our societies to continue operating as we know it.
But the IPCC AR6 also provides hope, if we are willing to embrace change. Some consequences of the climate crisis are already unavoidable or irreversible, but deep, rapid and sustained emissions reductions can still limit the impact. The scientific consensus is that to have a 67 percent chance of staying within 2 degrees C, we must cut down emissions by about 13 to 15 gigatons (Gt) by 2030. If we want to reduce the risks and costs further and stay within 1.5 degrees C, the cuts needed are between 20 and 23 Gt.
For comparison, the annual emissions of the USA are a bit below 6 Gt. The 27 EU members together emit about 3.5 Gt. You read that right. The world needs to reduce by 2030 the equivalent of more than twice the emissions of the USA to stay within 2 degrees C, and by 3 to 4 times to stay within 1.5 degrees C. While utterly feasible, the magnitude of the effort is, to say the least, challenging.
Where will these emissions reductions come from? The IPCC AR6 provides important information to guide decision-making, which is summarized in this graphic.
This graphic provides rich food for thought, but two things stand out. The first is that a substantial level of emissions reductions from renewable energy and transportation is good business. You can see that in the increased penetration of renewables in the energy mix and of electric vehicles in the transportation sector. The second is the potential contribution from avoided ecosystem conversion and restoration.
Add to this the current mitigation commitments from industrialized and non-industrialized economies and there is an emerging sense of a significant untapped opportunity in nature-based solutions to climate change. On one hand, it is becoming increasingly clear that the transition in the renewable and transportation sectors is encountering some limits to speed and scale. Bottlenecks in grid expansion and their impacts on the energy transition are just one example. On the other hand, ecosystem loss and degradation are following negative historical trends and continue to provide a substantial share of carbon emissions. But as the graphic shows, if this trend is to be reversed, nature-based solutions, particularly forests, could fill a substantial part of the emissions gap at an affordable cost. It would be difficult to identify any other viable path to reducing an additional 4 - 6 Gt by 2030.
Timing also matters. There are high-risk tipping points for ecosystems. The conversion of the Amazon to a savannah would be a global disaster of unimaginable proportions. Stopping and reversing ecosystem loss by 2030 must become an immediate policy priority. Not just on biodiversity and social grounds but also on carbon grounds.
We need to keep the pressure on non-nature sectors to continue along their decarbonization pathways, but we also need to urgently increase our funding and incentives, particularly a fair forest carbon price, to ensure that nature-based solutions achieve their mitigation potential in the next seven years. If not, even staying within 2 degrees C will be impossible.
