Documents Lenton, Timothy M. 3 results

"The ‘climate crisis' describes human-caused global warming and climate change and its consequences. It conveys the sense of urgency surrounding humanity's failure to take sufficient action to slow down, stop and reverse global warming. The leading direct cause of the climate crisis is carbon dioxide (CO2) released as a by-product of burning fossil fuels,i which supply ~87% of the world's energy. The second most important cause of the climate crisis is deforestation to create more land for crops and livestock. The solutions have been stated as simply ‘leave the fossil carbon in the ground' and ‘end deforestation'. Rather than address fossil fuel supplies, climate policies focus almost exclusively on the demand side, blaming fossil fuel users for greenhouse gas emissions. The fundamental reason that we are not solving the climate crisis is not a lack of green energy solutions. It is that governments continue with energy strategies that prioritize fossil fuels. These entrenched energy policies subsidize the discovery, extraction, transport and sale of fossil fuels, with the aim of ensuring a cheap, plentiful, steady supply of fossil energy into the future. This paper compares the climate crisis to two other environmental crises: ozone depletion and the COVID-19 pandemic. Halting and reversing damage to the ozone layer is one of humanity's greatest environmental success stories. The world's response to COVID-19 demonstrates that it is possible for governments to take decisive action to avert an imminent crisis. The approach to solving both of these crises was the same: (1) identify the precise cause of the problem through expert scientific advice; (2) with support by the public, pass legislation focused on the cause of the problem; and (3) employ a robust feedback mechanism to assess progress and adjust the approach. This is not yet being done to solve the climate crisis, but working within the 2015 Paris Climate Agreement framework, it could be. Every nation can contribute to solving the climate crisis by: (1) changing their energy strategy to green energy sources instead of fossil fuels; and (2) critically reviewing every law, policy and trade agreement (including transport, food production, food sources and land use) that affects the climate crisis."

"Economists have predicted that damages from global warming will be as low as 2.1% of global economic production for a 3$^\circ$C rise in global average surface temperature, and 7.9% for a 6$^\circ$C rise. Such relatively trivial estimates of economic damages -- when these economists otherwise assume that human economic productivity will be an order of magnitude higher than today -- contrast strongly with predictions made by scientists of significantly reduced human habitability from climate change. Nonetheless, the coupled economic and climate models used to make such predictions have been influential in the international climate change debate and policy prescriptions. Here we review the empirical work done by economists and show that it severely underestimates damages from climate change by committing several methodological errors, including neglecting tipping points, and assuming that economic sectors not exposed to the weather are insulated from climate change. Most fundamentally, the influential Integrated Assessment Model DICE is shown to be incapable of generating an economic collapse, regardless of the level of damages. Given these flaws, economists' empirical estimates of economic damages from global warming should be rejected as unscientific, and models that have been calibrated to them, such as DICE, should not be used to evaluate economic risks from climate change, or in the development of policy to attenuate damages."

"Transforming towards global sustainability requires a dramatic acceleration of social change. Hence, there is growing interest in finding ‘positive tipping points' at which small interventions can trigger self-reinforcing feedbacks that accelerate systemic change. Examples have recently been seen in power generation and personal transport, but how can we identify positive tipping points that have yet to occur? We synthesise theory and examples to provide initial guidelines for creating enabling conditions, sensing when a system can be positively tipped, who can trigger it, and how they can trigger it. All of us can play a part in triggering positive tipping points."