We can finally measure the damage each new coal, gas or oil project will do to people and nature

We have long known every tonne of carbon dioxide matters to the climate. But governments keep approving new fossil fuel projects – even as climate change worsens.

Until now, it’s been difficult to say how much damage and extra warming a specific project will do. Fossil fuel companies – and government agencies approving their projects – have often relied on what’s known as the “drop in the ocean” defence.

While backers concede a new project will add more carbon dioxide emissions to the atmosphere, they say these are tiny compared to the global tally and that it’s almost impossible to track damage attributable to the emissions of an individual project.

This defence won’t work any more. In recent years, attribution science has advanced rapidly, allowing scientists to pinpoint the role of climate change in making disasters and extreme weather more likely.

Our new open-source climate tool – the Carbon Impacts Tracer – goes one step further. It shows how much a new project will warm the planet – and how much damage it will do across eight areas, from loss of crops to heatwave deaths in Europe.

This will help make fossil fuel companies and governments approving these projects accountable for the damage they will do.

How did we get here?

To measure the damage attributable to a single fossil fuel project, we connected the dots between emissions produced, extra warming and the damage done to people and the environment.

Last year, experts from six universities in Australia and the United Kingdom released research on the damage that corresponds with emissions from the newly approved Scarborough gas project in Western Australia. Three of this article’s authors were involved.

This found that 876 million tonnes of CO₂ emissions from the Scarborough project would expose an extra 516,000 people worldwide to unprecedented heat. They would also result in 484 heat-related deaths in Europe by 2100 and destroy millions more coral colonies during every future mass bleaching on the Great Barrier Reef.

Our new tool gives users the ability to use the same robust methodology on any fossil fuel project.

How can we track the damage from one project?

The more carbon dioxide we add to the atmosphere, the hotter the planet gets.

The relationship is nearly linear. For every trillion (thousand billion) tonnes of carbon dioxide emitted into the atmosphere, the globe will warm about 0.45°C, according to the latest Intergovernmental Panel on Climate Change assessment report. As of 2019, cumulative global emissions are about 2.4 trillion tonnes.

Our Carbon Impacts Tracer uses this relationship to calculate the extra warming caused by a new project’s publicly documented carbon emissions. It then calculates the damage it will do across eight areas, including how many more people will be exposed to dangerous heat globally, how much glaciers will melt and how many Europeans will die due to heatwaves.

The tool uses only published studies robust enough to quantify the link between higher global temperatures and a specific type of damage. This high evidence threshold is why we only include eight types of damage at present. We will add more types of damage once the evidence base is robust enough.

For instance, the link between European heatwave deaths and climate change is robust and reproducible. But we don’t yet have research which meets our criteria for heatwave deaths in Australia or elsewhere.

What our tool does is bring together crucial scientific findings to measure how emissions lead to warming and subsequent damage.

Tracking the damage

Our tool lets users see the damage that will flow from five proposed Australian fossil fuel projects and one in the United Kingdom.

For example, Woodside’s proposed Browse to North West Shelf gas project will add 1,597 megatonnes of CO₂ over its lifetime. It will warm the planet 0.00072°C, which translates to almost 200,000 more people enduring an extra week of dangerous heat every year.

The tool also tracks future damage from 16 major fossil fuel companies between 2024 and 2050. For instance, ExxonMobil’s future emissions of 5,245Mt represent an extra 0.0024°C of warming which means an extra 127km² of glaciers will melt.

Users can also input carbon emissions from any project, company or country around the world to quantify the damage and generate reports showing the impacts, as well the underpinning science and references.

From the courtroom to the boardroom

For years, the difficulty of tracing a direct link between emissions and resulting damage made it harder to launch climate legal cases.

Last year, the world’s top court – the International Court of Justice – found fossil fuel production and expansion “may constitute an internationally wrongful act”, attributable to the nation where extraction is happening. The court recognised it was possible to establish a causal link between emissions and climate harms.

The Carbon Impacts Tracer shows the robust causal links between project and harms. It will be useful to communities and organisations seeking to attribute legal responsibility for climate harms to governments and fossil fuel companies, as well as to insurers and decision-makers assessing climate impacts.

Time for accountability

For decades, fossil fuel producers have been able to extract oil, gas and coal and emit pollution to the atmosphere with virtual impunity – even as climate change worsens and damages mount.

But we are entering a new era of accountability. Now that climate attribution science has come of age, it’s no longer possible to hide behind the argument that a new gasfield is just a drop in the ocean.

We can now see just how much damage that drop will do to the climate, nature – and to us.