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

This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: 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 cause. Fossil fuel companies—and government agencies approving their projects—have often relied on what's known as the "drop in the ocean" defense. While backers concede a new project will add more carbon dioxide emissions to the atmosphere, they say those emissions are tiny compared with the global total and that it's almost impossible to track damage attributable to an individual project.

This defense won't work anymore. 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 cause across eight areas, from crop losses to heat wave deaths in Europe. This will help hold fossil fuel companies and governments approving these projects accountable for the damage the projects will cause. To measure the damage attributable to a single fossil fuel project, we connected the dots between emissions produced, extra warming and damage to people and the environment.

Last year, experts from six universities in Australia and the United Kingdom published research on the damage associated with emissions from the newly approved Scarborough gas project in Western Australia. Three of this article's authors were involved. The research 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 apply the same robust methodology to any fossil fuel project. The more carbon dioxide we add to the atmosphere, the hotter the planet gets.