Fossil fuel reserves contain 3.5 tn tonnes of CO2

Human activity since the Industrial Revolution, largely powered by coal, oil and gas, has led to just under 1.2 degrees Celsius of warming and brought with it ever fiercer droughts, floods and storms supercharged by rising seas.

The United Nations estimates that Earth's remaining carbon budget -- how much more pollution we can add to the atmosphere before the 1.5C temperature goal of the Paris Agreement is missed -- to be around 360 billion tonnes of CO2 equivalent, or nine years at current emission levels.

The UN's annual Production Gap assessment last year found that governments plan to burn more than twice the fossil fuels by 2030 that would be consistent with a 1.5C world.

But until now there has been no comprehensive global inventory of countries' remaining reserves.

The Global Registry of Fossil Fuels seeks to provide greater clarity on oil, gas and coal reserves to fill knowledge gaps about global supply and to help policymakers better manage their phaseouts.

Containing more than 50,000 fields across 89 countries, it found that some countries on their own held reserves containing enough carbon to blow through the entire world's carbon budget.

For example, US coal reserves embed 520 billion tonnes of CO2 equivalent. China, Russia and Australia all hold enough reserves to miss 1.5C, it found.

All told, the remaining fossil fuel reserves contain seven times the emissions of the carbon budget for 1.5C.

"We have very little time to address the remaining carbon budget, said Rebecca Byrnes, deputy Director of Fossil Fuel Non-Proliferation Treaty, who helped compile the registry.