In recent years, the renewable technology sector has grown, particularly in solar, wind, and electric vehicles. This positive trend is welcome and must continue.
But to reduce emissions, we need to stop burning fossil fuels. Without carbon capture and storage, that means progressively phasing out coal, oil, and gas.
This means early retirement of existing fossil fuel infrastructure, particularly in developing countries that are currently increasing their stock of infrastructure despite cancelling some projects.
As fossil fuel infrastructure declines, low carbon infrastructure has to grow to replace it, while still maintaining security of energy supply. For this to happen with higher levels of renewable energy penetration, we will need new technologies, such as batteries and power demand management.
Very few scientists are happy to answer this question, particularly in a public forum.
Some are concerned the wrong answer may slowdown current mitigation efforts. Others argue it is not our role as scientists to prejudge what is feasible. Yet others argue that feasibility changes over time.
I see my role as a scientist to point out the obstacles and challenges, not just tell the positive news stories so others can sleep well at night. Understanding feasibility is important to adequately plan for adaptation and to ensure we get mitigation policies right.
Yes, I think “well below” two degrees is feasible in a model, in a theoretical sense. But not in practice. Why not?
First, policy will move along slower than expected because politicians have to balance competing objectives, and it is hard to see that climate will be the policy area that trumps all others.
Second, I am confident we will make technological progress in key areas, with government and business support, but I am less confident we can retire existing fossil fuel infrastructure at the required rates.
Third, carbon dioxide removal technologies are technically feasible, but I am sceptical that we can reach the scale of carbon dioxide removal required.
And finally, the most challenging mitigation will be in the countries that most desperately need economic growth.
My pessimism does not mean we should not try. It is important to distinguish between ambition and feasibility, and we can’t preclude technological, political, or social breakthroughs.
The only hope, is to hope that I am wrong.