The Urgency of Climate Overshoot: Exceeding 1.5°C Is Almost Inevitable

Despite global climate goals aiming to limit warming to 1.5°C, recent data shows that this threshold is rapidly approaching. With emissions still on the rise, the planet is now edging closer to 1.4°C of warming, making a temporary overshoot of the 1.5°C target highly likely.

In response, a growing conversation is emerging among scientists, policymakers, and civil society: What does it mean to “keep 1.5°C alive” in the era of climate overshoot?

New Review Offers Roadmap for Understanding Climate Overshoot

A comprehensive review published in the Annual Review of Environment and Resources addresses this critical issue. Written by a global team of climate scientists and policy experts—including contributors to the IPCC—the study examines:

• Climate risks during and after overshoot
• Adaptation and vulnerability factors
• Emission reduction strategies
• Global and national policy implications

The review introduces a conceptual framework to understand how climate risks evolve when global temperatures exceed 1.5°C, and what actions could reverse that trend.

Risks and Realities in a World That Exceeds 1.5°C

Overshooting 1.5°C, even temporarily, will have undeniable and potentially irreversible impacts. The review highlights risks such as the permanent loss of ecosystems, more extreme and frequent weather events, and cascading effects that worsen global inequalities. There is also concern about crossing tipping points like the melting of major ice sheets or dieback of the Amazon rainforest, which could push the climate into an entirely new and dangerous state.

Even if the temperature is brought back down, the damage done during the overshoot period would not be fully erased. However, returning to or below 1.5°C would still significantly lower future risks compared to staying at higher levels indefinitely. In this context, effective adaptation strategies become essential—not only to protect vulnerable communities during the overshoot phase, but to manage the longer-term consequences as well.

Pathways Back from Overshoot: What Could Work?

To cool the planet after surpassing 1.5°C, the review identifies several key strategies. These include scaling up carbon dioxide removal (CDR) technologies, aggressively cutting down residual CO₂ emissions, and reducing short-lived climate pollutants like methane. Achieving these goals would require efforts that go far beyond current national climate targets and demand strong global coordination.

The review makes it clear that the feasibility of returning to 1.5°C depends on how far we overshoot. The lower the peak temperature, the more realistic the recovery becomes—both technically and economically. Quick, decisive action to reduce emissions in the near term is therefore critical. This not only limits the extent of the overshoot but also keeps open the possibility of recovery.

A Complex Climate Journey Shaped by Policy and Equity

The path through and beyond climate overshoot is not a linear one. It is shaped by a complex web of trade-offs, political decisions, technological limits, and social preferences. Different regions and communities will experience the consequences differently, raising critical issues around climate justice, equity, and historical responsibility.

According to Professor Richard Betts from the University of Exeter and the UK’s Met Office, even if we manage to return to 1.5°C, the overshoot itself will leave lasting effects. But doing so would still be preferable to stabilizing at even higher levels of warming, where risks multiply and adaptation becomes far more difficult.

Tools and Resources for Navigating Overshoot

To support public understanding of these challenges, the Euro-Mediterranean Center on Climate Change (CMCC) has launched a new digital platform that offers science-based insights on what climate overshoot means and how it affects risk, mitigation, and adaptation planning. This initiative aims to empower decision-makers, researchers, and communities with the knowledge needed to make informed, climate-smart choices.

Is Returning to 1.5°C Still Possible?

While the idea of “keeping 1.5°C alive” may now include a temporary overshoot, the review reinforces that returning to this target—though difficult—is not impossible. However, it will require unprecedented collaboration, urgency, and innovation on a global scale.

Policymakers will need to navigate a range of options, balance priorities, and take bold, equitable actions. The window for avoiding the worst outcomes is narrowing, but it has not yet closed. The time to act is now.

Read the Original Article: Phys.org

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