For 50/50 chance of limiting rise in global temperatures to 1.5C, 19 countries including US and UK must end their energy production first, a new report says, adding poor oil producers like Angola could end production by 2050.
Rich countries must end their oil and gas production by 2034 to cap global heating at 1.5 degrees Celsius and give poorer nations time to replace fossil fuel income, according to a report.
The 70-page analysis from the Tyndall Centre for Climate Change Research comes on Tuesday as nearly 200 nations kick off a two-week negotiation to validate a landmark assessment of options for reducing carbon pollution and extracting CO2 from the air.
The overarching objective, enshrined in the 2015 Paris Agreement, is to cap global warming "well below" 2C, and 1.5C if possible.
Some poorer nations produce only a tiny percentage of global output but are so reliant on fossil fuel revenues that rapidly removing this income could undercut their economic or political stability, the Tyndall Centre report showed.
Countries such as South Sudan, the Republic of Congo and Gabon have little economic revenue apart from oil and gas production. By contrast, wealthy nations that are major producers would remain rich even if fossil fuel income were removed.
Phasing out coal first
Oil and gas revenue, for example, contribute eight percent to US GPD, but the country's GDP per capita would still be about $60,000 –– second highest in the world among oil and gas producing nations -–– without it, according to the report.
"We use the GDP per capita that remains once we've removed the revenue from oil and gas as an indicator of capacity," lead author Kevin Anderson, a professor of energy and climate change at the University of Manchester, told the AFP news agency.
There are 88 countries in the world that produce oil and gas.
"We calculated emissions phase-out dates for all of them consistent with the Paris Agreement temperature goals," Anderson said. "We found that wealthy countries need to be at zero oil and gas production by 2034."
The very poorest countries can continue to produce out till 2050, according to the calculation, and other countries such as China and Mexico are somewhere in between.
GDP deciding factor
For a 50/50 chance of limiting the rise in global temperatures to 1.5C, 19 countries in which per capita GDP would remain above $50,000 without oil and gas revenue must end production by 2034.
Included in this tranche are the US, Norway, Britain, Canada, Australia and the United Arab Emirates.
Another 14 "high capacity" nations where per capita GDP would be about $28,000 without income from oil and gas must end production in 2039, including Saudi Arabia, Kuwait and Kazakhstan.
The next group of countries –– including China, Brazil and Mexico –– would need to end output by 2043, followed by Indonesia, Iran and Egypt in 2045.
Only the poorest oil and gas producing nations such as Iraq, Libya and Angola could continue to pump crude and extract gas until mid-century.