A new scientific tool is helping translate carbon emissions from fossil fuel projects into measurable impacts on people and ecosystems. Called the Carbon Impacts Tracer, the tool uses peer-reviewed climate research to show how a specific quantity of carbon dioxide can contribute to extreme heat, coral bleaching, food production losses, glacier decline and heat-related deaths. Its developers hope that expressing emissions through tangible consequences will make the effects of individual fossil fuel projects easier for the public, governments and courts to understand.
One major example is the proposed extension of the Hunter Valley Operations (HVO) coal mine in New South Wales, Australia. If approved, the mine could continue operating until 2045 and generate the equivalent of approximately 809 million tonnes of carbon dioxide. Scientists estimate that these carbon emissions would contribute about 0.00036°C to global warming. While that number may appear extremely small, the Carbon Impacts Tracer demonstrates how even a tiny increase in global temperatures can have significant consequences when experienced across large populations and ecosystems.
According to the tool, emissions associated with the HVO project could expose almost half a million people to unprecedented heat. They could also contribute to the loss of nearly 15 million coral colonies on the Great Barrier Reef each time a major bleaching event occurs. In Europe, the additional warming could contribute to more than 100 extra heatwave-related deaths by the end of the century. These estimates demonstrate how small contributions to global temperature increases can translate into substantial real-world impacts.
Agriculture could also be affected. The additional heat associated with the mine’s carbon emissions is estimated to reduce crop production each year by an amount equivalent to the minimum dietary requirements of approximately 276,000 people. The tracer can perform similar calculations for emissions from individual projects, companies, governments or any known quantity of carbon dioxide. It currently measures impacts across eight different areas, including food production, glacier loss, coral mortality and labour hours lost because of excessive heat.
Central to the calculations is the Transient Climate Response to CO₂ Emissions (TCRE), an established scientific relationship between cumulative carbon dioxide emissions and global warming. The metric estimates that every trillion tonnes of CO₂ released causes approximately 0.45°C of global heating. Once the amount of CO₂ associated with a project is known, researchers can calculate its contribution to warming and compare that increase with findings from existing peer-reviewed climate studies.
Professor Sarah Perkins-Kirkpatrick of the Australian National University, who helped develop the tracer, argues that every tonne of carbon dioxide contributes to climate change. The results are presented as best estimates within ranges of uncertainty, and the tool provides links to the scientific studies supporting its calculations. This allows users to examine both the estimates and the research behind them.
The Carbon Impacts Tracer could also influence climate accountability and litigation. One difficulty in climate lawsuits has been establishing a connection between the carbon emissions of a particular corporation or government and specific environmental or human harm. Emitters have sometimes argued that their individual contribution is too small to measure against global emissions.
Researchers involved in the project say advances in climate attribution science are making those connections increasingly possible. By linking a known quantity of carbon emissions to additional warming and then connecting that warming to impacts such as extreme heat, coral loss and declining food production, the Carbon Impacts Tracer provides a new way to assess responsibility for climate damage. Ultimately, the tool demonstrates that even seemingly small contributions to global warming can produce measurable consequences when accumulated across people, ecosystems and economies.