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We need to prepare for a temperature overshoot and worse climate change

  • With global warming of 2.7 degrees Celsius by 2100 looming, adaptation finance for poor nations is more urgent than ever

  • Planet-cooling research into carbon dioxide removal and solar geoengineering must also be accelerated

Opinion by Muhamad Chatib Basri, former Minister of Finance of Indonesia & Xue Lan, Cheung Kong Distinguished Chair Professor and the Dean of Schwarzman College at Tsinghua University, members of The Climate Overshoot Commission, 10 December 2022

As the world’s population reaches 8 billion, the consequences of our environmental impact are visible and devastating, from melting glaciers to unprecedented heatwaves and floods. These are set to intensify, in frequency and severity – while countries continue to try to reduce greenhouse gas emissions to limit global warming to 1.5 degrees Celsius above pre-industrial levels.

Yet the latest mathematical models and reports from authoritative institutions in the UN and other expert organizations tell us the world is heading for an increase of temperatures that will overshoot the Paris Agreement’s ambitious goal of limiting global warming to 1.5°C, at least temporarily. Instead, we are on track for an expected warming scale of 2.7°C by 2100, due to the insufficient emissions reductions. What is decided today as a response to global warming will define the climate in which our children and grandchildren will live.

To address this unfortunate likelihood, we need to explore additional approaches to minimize the impacts of temperature overshoot and to reduce its length. Whilst emissions reductions remain the highest priority, what else do we need for global societies to adapt to the significant climate impacts that we are already experiencing? Could and should we consider cooling the earth? How do we capture the carbon dioxide emitted in the air since the industrial revolution a few hundred years ago?

The first additional approach that we need to explore is adaptation to a changed climate. It was already high on the agenda of the COP27 in Sharm El Sheikh where negotiators debated gaps of adaptation funding, which is pivotal to climate-vulnerable low- and middle-income countries. In fact, the annual USD 100 billion finance for climate action pledged at COP15 in Copenhagen is far from being delivered. Even this would be insufficient, since the UN reminds that “international adaptation finance flows to developing countries are 5-10 times below estimated needs and the gap is widening.” Furthermore, assistance for “losses and damages” which are not avoidable by adaptation measures is also an increasingly salient matter of equity and social justice for vulnerable countries and communities. We need to build adaptation programmes with local communities’ ownership and adherence, deliver promised finance, and to advance the discussion on loss and damage.

The second approach that is key to reducing the magnitude and length of climate overshoot is carbon dioxide removal (CDR). The UN’s IPCC concluded that CDR is unavoidable in scenarios that limit overshoot. These techniques that are being developed largely in high-income countries are lacking in developing ones, where nature-based solutions should be enhanced and accelerated by technological additions. In addition to the transfer of technologies and the development of local capacities, the full implications of CDR on social, economic and cultural rights and on the livelihoods of diverse communities and populations need to be fully taken into account.

The last approach, a more debated one, is solar radiation modification (SRM) or “solar geoengineering”, as experts refer to it. This would artificially lower the planet’s temperature, perhaps by mimicking volcanic eruptions’ natural cooling effect. SRM appears able to rapidly and inexpensively reduce global warming. It nevertheless bears risks, uncertainties, and serious governance challenges. One of them is its reported low cost and technical feasibility, which implies that a single country could undertake it, with global effects on other countries. The chance of such unilateral deployment could be lessened by putting SRM on the agenda of the international community to increase cooperation and collaboration. Another challenge is that information on the effectiveness of SRM is still limited and inconclusive, making it a non-viable option at this time. While SRM research is currently insufficient, and funding is limited, this research should still be developed as a last resort option if and when climate overshoot is unavoidable through emission cuts alone. As Singapore’s Prime Minister Lee Hsien Loong stated, SRM research—granted strict oversight–should be discussed to provide policymakers with an understanding of its optimal use should the need for it ever arise.

Rarely has the world been at an intersection of significant issues such as we are experiencing today, with compounding local, regional and global problems. From wars to global health threats and serious economic difficulties, policymakers need to strengthen their response to climate change by choosing the most effective, fair, and cost-effective solutions. It is estimated that the integration of CDR and SRM in climate-related economic models provides large economic benefits, in trillions of dollars per year of avoided damages, especially for low- and middle-income countries in warming climates. It is time for governments to assess the benefits, costs, and risks of each of these approaches, as they do for every public policy or service they provide. We look forward to accompany them through our work at the Climate Overshoot Commission, and to support them in identifying the best practice examples and most cost-effective models to address the likely risk of temperature overshoot.


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