Our Deadline

The science is clear: we are in a Climate Emergency

The Science

Decades of increasing carbon emissions are harming the natural and societal systems upon which humanity depends, threatening devastation if we do not act in time. The good news: there is still time.

Backed by the latest science, the Climate Clock tells us what we must do, by when. The Deadline and Lifelines on the Climate Clock make clear the speed and scope of action that political leaders must take in order to limit the worst climate impacts.

In 2018, the Intergovernmental Panel on Climate Change (IPCC) published a Special Report - the first attempt by climate scientists to measure a remaining global carbon budget that could feasibly keep global warming below 1.5ºC. In summer 2021, the IPCC published a report on the physical science behind climate change, which included updated carbon budget estimates for limiting global warming to 1.5ºC. In this report, IPCC researchers estimated that, beginning in 2020, humans could release an additional 400Gt of carbon into the atmosphere and still have a 67% chance of limiting warming to 1.5ºC (see here, table SMP.2).

The Climate Clock deadline shows how long we have left until this carbon budget runs out, given the amount of carbon we continue to emit globally. The clock will continue to run down until it hits zero, at which time our carbon budget would be depleted and the likelihood of even more devastating global climate impacts would be very high. We must take action to reduce global greenhouse gas emissions toward zero as quickly as possible within this critical time window for action.

Data for the deadline is sourced from the Mercator Research Institute on Global Commons and Climate Change. The MCC’s carbon clock assumes an average annual rate of 42.2 Gt of carbon emissions in order to calculate the time remaining on the clock. However, if rates of global emissions continue to rise, our carbon budget will run out even faster. If we cut the rate of global carbon emissions, time on the clock would hypothetically begin to increase.

Reference list

Mercator Research Institute on Global Commons and Climate Change

IPCC Report