Proposing a 1.0°C climate target for a safer future

Abstract

The Intergovernmental Panel on Climate Change concludes that climate change has already caused substantial damages at the current 1.2°C of global warming and that warming of 1.5°C would elevate risks of a wide-range of climate tipping points. For example, wet-bulb temperatures are already exceeding safe levels, and the melting of the Greenland and West Antartic ice sheets would lead to over ten metres of sea level rise, representing an existential threat to coastal cities, low-lying nation states, and human wellbeing worldwide. We call for a broad scientific discussion about a stricter and more ambitious climate target of 1.0°C by the end of this century. Comprehensive electrification and highly renewable energy systems offer a pathway to sub-1.5°C futures through rapid defossilisation and large-scale, electricity-based carbon dioxide removal. Independent scenarios show that restoring a stable and safe climate is attainable with coordinated policy and economic support.

Assessing changes in global fire regimes

“…However, we have exceeded the envelope of global fire behavior observed in the Holocene, meaning that human-fire interactions could have extreme and unexpected outcomes (Bova et al 2021;Hammond et al 2022). We should not assume that historical management practices will suffice (Pyne 2007;Crandall et al 2021;Ellis et al 2021) given accelerated rates of vegetation change (Mottl et al 2021;Słowiński et al 2022;Talucci et al 2022), climate destabilization (Armstrong McKay et al 2022;Breyer et al 2023), the emergence of novel biotic and abiotic conditions (Ordonez et al 2016;Finsinger et al 2017;Burke et al 2019), and increasing human population and affluence. For example, the expansion of human development in fire-prone areas in the western US is increasing both wildfire incidence and cost of suppression (Balch et al 2017).…”

“…However, there was a high level of agreement across fire regions that the risk of extreme fire behavior overwhelming the capacity of these fire management tools increases under higher greenhouse gas emissions. Although the specific consequences vary by fire region and habitat type, the overall message is clear: rapid reduction of greenhouse gas emissions is needed to restore Holocene-like climate conditions (Cyr et al 2009;Abbott et al 2022;Breyer et al 2023;Burton et al 2023). This would reduce the difference between natural and managed environments and ensure long-term conservation of ecosystem functions and services, thereby preserving socioeconomic benefits (Führer 2000;Gauthier et al 2009).…”

The carbon dioxide removal gap

“…• The scenario is permitted to initially exceed a warming target and compensate for this with net negative emissions later in the century (overshoot) 24 • A temperature target is chosen that has already been overshot, such as 1°C 27 • Emissions reductions are faster and implemented without delay 22,23 • A wider portfolio of (demand-side) mitigation options are available, with lower costs relative to CDR 28,29…”

Accelerating the Renewable Energy Revolution to Get Back to the Holocene

“…Despite convincing evidence that 1.5°C of warming would cause immense disruption to Earth systems, especially human civilization, many policymakers and researchers continue to treat this target as acceptable, or at least as the best future that remains attainable. If sustained through the end of the century or longer, this level of warming would very likely result in immense damage to human society, pervasive decline of life on Earth, and transformation of Earth's physical structure (Armstrong McKay et al., 2022; Breyer et al., 2023; IPCC, 2021; Rockström et al., 2023; Willcock et al., 2023). More immediately, the continued use of fossil fuels associated with 1.5–2°C scenarios would result in hundreds of millions of avoidable deaths caused by fossil fuel pollution, which currently accounts for one in five premature deaths globally and imposes approximately US $10 trillion annually in economic damages (Errigo et al., 2020; Fuller et al., 2022; Galimova et al., 2022; Vohra et al., 2021).…”

“…The development and deployment of renewable energy technologies are more than 30 years ahead of projections (Figure 1), making clean electrification of the entire economy possible and macroeconomically profitable (Bogdanov et al., 2021; Breyer et al., 2022; Jacobson et al., 2022; Way et al., 2022). This renewable energy revolution has eliminated tradeoffs between economic development and climate mitigation, rendering obsolete many of the techno‐economic assumptions in integrated assessment models and fundamentally changing the terms of debates about climate, pollution, and sustainable development (Breyer et al., 2023; Fuller et al., 2022; San‐Akca et al., 2020; Way et al., 2022).…”