2022-11-30 Climate change mitigation: time for action by Céline Guivarch (IPCC AR6 Working group 3: Mitigation of Climate Change)

Introduction

With its 3,000 pages, over 18,000 peer-reviewed academic papers, 278 lead authors and thousands of contributors, the IPCC report published in April 2022 represents the most up-to-date scientific knowledge on climate change mitigation.

In case you haven’t had time to read the extensive report, its key messages are summed up here, in the hope that it will encourage you to go further.

In 2021, the first part of the IPCC report , on the physical basis of climate change, established the human impact on global warming as an unequivocal fact: 1.1°C above pre-industrial levels, the highest level in 100,000 years .

A few months later, the second part of the report showed the ripple effects of this warming on ecosystems and human societies.

It also focused on solutions for adapting to a changing climate, but also the limitations of these solutions.

The third part of the report builds on these findings, summarizing scientific knowledge on past emissions and the outlook for future emissions, options for reducing emissions, climate change policies, the financing and the innovations they require. What does this report tell us ?

A critical decade (2020-2030)

Despite the growing number of policies and measures, in numerous countries and at all levels of government, greenhouse gas (GHG) emissions remain high.

These policies and measures have helped prevent emissions, but only slowed their rate of growth at the global level, without reversing the trend.

As such, GHG emissions, which accumulate in our atmosphere and cause climate change, have never been higher in absolute terms.

Yet, in order to pursue a pathway compatible with limiting global warming to 2°C, global emissions must be reduced by 20 to 30% by 2030, compared to their level in 2019. And to limit warming to 1.5°C, they must be cut in half.

This means that the present decade is critical to initiate and accelerate a reduction in global GHG emissions, and set in motion the transformations needed in key sectors – energy, industry, transport, building, infrastructure, cities, the agri-food systems, among others.

Regardless of the targeted level for global warming stabilization, we must achieve net zero CO2 emissions (also known as CO2 neutrality or carbon neutrality), and reduce other GHGs – methane, nitrous oxide, fluorinated gases.

In pathways compatible with 1.5°C, this carbon neutrality is to be achieved around 2050, and around 2070 for 2°C pathways.

Limiting the extent of climate change

While major transformations are needed in all key sectors, solutions are available.

There are options for reducing emissions that cost less than $100 per ton of CO2, which could cumulatively halve global GHG emissions by 2030.

Such options include technologies for generating renewable (solar, wind) or nuclear electricity, solutions for reducing the leakage of methane and fluorinated gases, storing carbon in agricultural soils, restoring ecosystems and forests, solutions for energy conservation and efficiency in buildings, developing public transport and active mobility (cycling and walking), the electrification of vehicles, solutions for using energy and materials efficiently in industry, and recycling.

The report focuses especially on actions related to demand (for energy, materials, goods, land, water) and highlights the potential to significantly reduce emissions – by 40-70% – by 2050. Some of these actions are based on adopting technologies, while others involve efficiency and sufficiency.

Examples of such actions in the building sector include:

  • installing solar panels on roofs (technology)

  • insulation (efficiency)

  • setting heating to 19°C instead of 20°C (sufficiency)

  • In the transportation sector, actions are based on an “avoid, shift improve” model. For example:

    • avoiding travel needs, through urban planning to shorten distances between homes, workplaces, schools, shops etc.

    • avoiding the movement of goods by shortening supply chains, shifting from high-emission (planes, cars) to low-emission (rail, public transportation) or zero-emission (cycling, walking) modes of transportation

    • improving vehicles by making them light, electric etc.

The report underscores that these demand-side actions are not the responsibility of end users alone, but require collective action and public policies to transform infrastructure, and build and enable access to carbon-free alternatives for everyone.

Cities on the front lines

The report also focuses on cities, which concentrate people and activities, and therefore emissions, but also offer ways to reduce them: urban planning, buildings, transportation networks, improving carbon uptake and storage (by adding trees, vegetation, green spaces, ponds).

The latter option is also a way to adapt to urban heat island effects during heat waves, which become more frequent with every fraction of a degree of warming.

The costs of a number of these options for reducing emissions have dropped significantly with their recent deployment (for example, the cost of solar energy has decreased tenfold over the past decade).

Moreover, it has become clear that the macroeconomic cost of action to reduce emissions is lower than the cost of inaction: taking action to limit the extent of climate change costs less than suffering from the damage it causes.

However, the report shows that the major transformations needed to reduce emissions cannot be carried out on an incremental basis and highlights the barriers to initiating these transformations.

Barriers to climate change mitigation

Some barriers are physical in nature .

For example, if already-existing fossil fuel-related infrastructure (coal, gas or oil-fired power plants, industrial facilities, internal combustion vehicles etc.) is used until the end of its technical lifetime, this would exceed the emissions budget consistent with 1.5°C warming.

Other barriers are financial .

Depending on the sector and region, the investments observed are 3 to 6 times lower than the level of investment needed for mitigation.

The investment gaps are the widest in developing countries, and in the transportation, agriculture and forestry sectors.

However, there is sufficient capital available globally to close these gaps. This would require redirecting investment, which still overwhelmingly finances fossil fuels, towards mitigation solutions.

Still other barriers are institutional .

The magnitude of the transformations that must be carried out call for ambitious, coordinated action between all levels of government – from territories, regions, and countries to the European and international level – in an extremely unequal world.

At the global level, the richest 10% of countries are responsible for roughly 40% of emissions, while the poorest 50% are responsible for less than 15% of emissions.

International solidarity is needed to respond to the issues of climate change, technology transfer and international funding of actions to reduce emissions.

Exploring potential synergies

To help overcome these barriers, the report explores potential synergies with other development goals (such as eradicating poverty, improving health, education, and reducing inequality). Multiple synergies are possible in the area of health, for example. Limiting the burning of fossil fuels reduces greenhouse gas emissions and also reduces local pollutants that are harmful to health.

Developing active forms of mobility reduces emissions and combats physical inactivity. Eating a diet with less meat, in keeping with nutritional guidelines, keeps people healthy and reduces methane emissions.

The report also highlights approaches to a “just” transition, allowing everyone to find their place in a future low-carbon world.

These approaches take into account the issue of inequality, from the mitigation policy design stage. They involve education, professional retraining, and collectively constructed alternatives.

Preventing the worst effects

The evidence is clear: urgent action is needed to reduce emissions and prevent the worst effects of climate change. Each additional fraction of a degree gives rise to additional risks and damage.

The solutions for reducing greenhouse gas emissions are well-known.

We have the tools to implement these solutions, while improving well-being for all.

We are on the cusp of decades of extensive action to radically transform all major systems and achieve net zero CO₂ emissions. And this decade is critical to set these changes in motion.

What role will you play in these transformations ?

This is a real question.