The global effort to limit warming to 1.5°C—a goal enshrined in the 2015 Paris Agreement—has always been fraught with complexities.

While technological advances and economic strategies have been extensively debated, a recent study published in Nature Climate Change suggests that the ability of governments to effectively implement climate policies is, in fact, the most critical determinant in meeting this target. This study adds a new dimension to our understanding of climate change mitigation by highlighting the often-overlooked political and institutional constraints that play a pivotal role in shaping our planet's future.

Over the past few decades, the scientific community has developed various pathways to demonstrate how the world might reduce greenhouse gas emissions and limit global warming.

The Intergovernmental Panel on Climate Change (IPCC) has suggested that, with rapid decarbonization and the deployment of renewable energy technologies, it is technically feasible to cap warming at 1.5°C. However, the new study indicates that when political and institutional constraints are factored into these scenarios, the outlook becomes far more challenging.

It is not just a matter of having the right technology or the economic means, but about whether governments can create and enforce policies effectively enough to drive the necessary change.

Understanding Emissions Scenarios

When the Paris Agreement was signed in 2015, nearly every country in the world committed to limiting global warming to "well below" 2°C above pre-industrial levels, with an aspirational goal of capping the increase at 1.5°C.

Since then, many nations have set ambitious net-zero targets and have made varying degrees of progress towards these goals. Yet, as the Earth continues to warm, some scientists have begun to question whether the 1.5°C target remains attainable.

The IPCC’s special report on 1.5°C, released in 2018, highlighted several factors that could potentially impede the world’s ability to meet this target. These include technological, economic, and sociocultural barriers, as well as the political and institutional challenges discussed in the recent study.

To explore future warming scenarios, the IPCC uses integrated assessment models (IAMs) that consider a range of factors, from energy technologies to societal trends. Of the thousands of scenarios these models produce, fewer than 100 predict that global warming could be limited to 1.5°C with little or no overshoot. These are known as "C1 scenarios."

However, even these scenarios do not fully account for the political and institutional feasibility constraints identified in the new research. For example, while some scenarios assume that rapid decarbonisation began almost immediately after 2019, in reality, global emissions have continued to rise, reducing the remaining carbon budget for staying within the 1.5°C limit more quickly than anticipated.

Political and Institutional Constraints

The study identifies several constraints that affect the feasibility of limiting global warming. The first two—geophysical and technological—address the limitations posed by current technology and the Earth’s physical capacity to store carbon. For example, the development of carbon capture and storage (CCS) technologies and the expansion of solar and nuclear power are essential to decarbonisation efforts but face significant technical and financial challenges. The study also considers sociocultural constraints, such as behavioural changes that could reduce energy demand, and economic constraints, such as the implementation of carbon pricing.

However, the most significant contribution of the study is its focus on "institutional constraints," which it describes as a government’s ability to effectively implement climate mitigation policies. This includes a wide range of factors, from the speed and efficacy of policy implementation to the level of public and political support for climate action. Different countries possess varying levels of institutional capability, which can influence their ability to enforce environmental regulations or introduce carbon pricing mechanisms.

For instance, wealthier nations may have more robust governance structures and can more easily implement changes, while less wealthy nations might struggle due to weaker governance and limited resources. The study uses a "governance indicator" to estimate how quickly countries are expected to decarbonise, based on how effectively they have achieved past environmental goals. Countries that have successfully reduced sulphur emissions from power plants, for instance, receive higher governance scores, while those that have struggled with policy implementation are scored lower.

Implications for Global Warming Targets

By incorporating these governance indicators into their models, the researchers created a range of scenarios to assess how different levels of political and institutional capacity might affect global emissions and warming targets. In their most optimistic scenario, countries with high governance scores implement strong carbon pricing and emissions reduction measures, making it feasible to achieve the 1.5°C target.

In their "default" scenario, both carbon prices and emissions reductions are constrained, and in a pessimistic scenario, governance levels remain at their 2020 levels throughout the 21st century.

The findings reveal that even with technological advances and potential economic incentives, the political and institutional barriers significantly reduce the likelihood of meeting the 1.5°C target. In scenarios with no institutional constraints, nearly all models could align with the IPCC's C1 scenarios, offering a more than 50% chance of staying below a peak temperature of 1.6°C. However, when institutional constraints are added, this probability drops dramatically, underscoring the critical role that governance plays in achieving climate goals.

Can We Still Achieve the 1.5°C Target?

The study’s findings have profound implications for the future of global climate policy.

While the researchers do not suggest that the 1.5°C target should be abandoned, they emphasize the need to prepare for the possibility of exceeding this limit, even under the most ambitious mitigation scenarios. This could mean a peak temperature of 1.6°C or higher, with the hope that temperatures could be brought back down below 1.5°C by the end of the century. However, this approach carries significant risks, including the potential crossing of tipping points that could lead to irreversible changes in the climate system.

The study’s authors argue that the 1.5°C target was always a highly ambitious goal, given the real-world technical, institutional, economic, and political constraints that shape climate policy.

Yet, the progress made in recent years—particularly in terms of technological advancements and the adoption of renewable energy—demonstrates that meaningful action is possible. For example, the rapid deployment of solar and wind power, along with the increasing affordability of electric vehicles, has shown that a transition to a low-carbon economy is not only feasible but also economically advantageous in many contexts.

The Need for Stronger Governance and Policy

The research underscores the importance of strengthening governance and policy frameworks to accelerate the transition to net-zero emissions. This involves not only setting ambitious targets but also ensuring that governments have the capacity and willingness to implement the necessary policies.

In many cases, this will require overcoming significant political and economic barriers, particularly in countries where fossil fuel interests remain powerful and climate action is politically contentious.

The study highlights the need for a comprehensive approach to climate policy that goes beyond technological solutions and economic incentives. It calls for a deeper understanding of the political and institutional dynamics that shape climate action and for more effective strategies to build public and political support for ambitious climate policies. This includes fostering greater international cooperation, supporting capacity-building efforts in developing countries, and ensuring that climate policies are designed in a way that is both equitable and effective.

A Call to Action for Governments Worldwide

As the study shows, the path to achieving the 1.5°C target is fraught with challenges, but it is not insurmountable.

The technological and economic tools needed to transition to a low-carbon future are largely available, but their deployment depends on the political will and governance capacity of individual countries. This is where international collaboration becomes crucial. Developed countries must take the lead in reducing their own emissions while also providing financial and technical support to developing countries.

Furthermore, there is a need for greater transparency and accountability in climate governance.

Governments must be held accountable for their commitments and actions, and there should be mechanisms in place to ensure that climate policies are implemented effectively and fairly. This includes regular monitoring and reporting on progress towards emissions reduction targets, as well as mechanisms for reviewing and strengthening climate policies over time.