The Challenge of Overshooting the 1.5°C Temperature Target
Since the adoption of the Paris Agreement nearly a decade ago, the goal of keeping the global average surface temperature increase below 1.5°C has been the focal point of the climate movement. However, recent remarks by the UN Secretary General António Gutierres have highlighted the inevitability of overshooting this target due to insufficient action to cut emissions.
This news, while not surprising to climate scientists, is disheartening as it signifies the intensification of climate impacts and the widening gap between those responsible for climate change and those most affected. The failure of political leaders and the fossil fuel industry to take adequate action has led us to this point, with ethical implications that will extend across generations.
Understanding Overshoot and its Implications
Overshoot, in the context of the Intergovernmental Panel on Climate Change (IPCC), refers to scenarios where the global average temperature exceeds 1.5°C but includes a pathway to return below this threshold by the end of the century. This trajectory to bring temperatures back down requires aggressive action to reduce emissions and draw down heat-trapping gases in the atmosphere.
The consequences of overshoot include increased risks of severe and irreversible climate impacts. Extreme events like heatwaves and precipitation will become more frequent and intense, while sensitive ecosystems like coral reefs face significant decline. The loss of glaciers, melting ice sheets, and potential collapse of ocean currents all contribute to irreversible changes with far-reaching consequences.
Challenges in Bringing Temperatures Back Down
Bringing temperatures back down after overshoot requires significant action and technology that have yet to materialize at the necessary scale. Emissions need to be drastically reduced, stabilized, and eventually reversed to achieve net negative emissions. However, current efforts, as seen through Nationally Determined Contributions (NDCs) and carbon removal technology, fall short of the required magnitude.
Deploying widespread carbon dioxide removal (CDR) and enhancing land carbon sinks are essential but face economic, technical, and feasibility challenges. The scale of net negative emissions needed to lower temperatures by even a small fraction is immense and requires a level of commitment and innovation that has not been achieved to date.
Potential for Action Amidst Obstacles
Despite the challenges of overshoot, there are opportunities for action to mitigate its impacts and work towards a more sustainable future. Investments in resilience, collective decision-making, and a focus on equity and justice in deploying CDR can shape the trajectory of climate change. While the reality of overshoot is daunting, it should not deter us from taking meaningful action to address the climate crisis.
