1.5C cap could save trillions

Failing to cap global warming at two degrees Celsius or less could cost the world economy tens of trillions of dollars over the next 80 years, researchers warned Wednesday.

Four-fifths of countries and 90 percent of the global population, in other words, stand to reap major economic benefits by avoiding costs linked to higher temperatures, they reported in the journal Nature.

Such costs stem from more frequent and severe extreme weather, lower yields in agriculture, and negative health impacts.

The 196-nation Paris climate treaty calls for holding the rise in Earth's surface temperature to "well under" 2 C (3.6 degrees Fahrenheit), and 1.5 C if possible.

The lower target was included in light of severe climate impacts after only 1 C of warming, including deadly heatwaves, droughts, and storms surges made more destructive by rising seas.

A UN special report due in October will detail likely damage in a 1.5 C world, and help leaders decide if the target is within reach.

But few efforts have been made to quantify the impact of different temperature goals on long-term economic growth.

"Achieving the more ambitious Paris goals is highly likely to benefit most countries -- and the global economy overall -- by avoiding more severe economic damage," said senior author Noah Diffenbaugh, a professor at Stanford University's School of Earth.

Over the course of the century, the global economy in a 1.5 C world would generate an additional 20 trillion dollars in GDP compared to one in which temperatures rise by 2 C, the study found.

There would be exceptions: the economies of Russia, Canada, Nordic and Baltic nations, and central Europe would all take a hit in a 1.5 C scenario.

Diffenbaugh and colleagues made their calculations by studying how economic performance over the last 50 years, measured by GPD, matched changes in temperature around the world.