"The window on keeping global warming below 1.5 degrees C is closing rapidly and the current emissions pledges made by signatories to the Paris Agreement do not add up to us achieving that goal", added King.
This would mean replacing petrol and diesel cars with electric vehicles or other clean alternatives and scrapping the use of gas boilers in homes in just a few decades.
Four scenarios are modeled in the report that reflect different strategies governments could take to deliver "no or low overshoot" of the 1.5°C target.
The latest report from the United Nations' Intergovernmental Panel on Climate Change (IPCC) is, honestly, the sort of thing that should force the world's citizens out into the streets. It's intended as a guide for policymakers who are aiming to limit temperature rise to the target 1.5 degrees Celsius.
Global temperature is now rising 0.2C with each decade, and it is estimated we will reach 1.5C by 2040.
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"This report is not a wake-up call, it is a ticking time bomb", said Gro Harlem Brundtland, Acting Chair of The Elders in a statement. The estimated $54 trillion in damage from 2.7 degrees of warming would grow to $69 trillion if the world continues to warm by 3.6 degrees and beyond, the report found, although it does not specify the length of time represented by those costs.
Allowing the global temperature to temporarily exceed or "overshoot" 1.5ºC would mean a greater reliance on techniques that remove Carbon dioxide from the air to return global temperature to below 1.5°C by 2100.
Warrick said her organisation intends to campaign for governments to invest in carbon capture technology. It encompasses 195 member states and is tasked with assessing science related to climate change and providing guidelines for policy makers.
"There will be 420 million people less suffering because of climate change if we would be able to limit the warming to 1.5°C level and we have certain areas in the world which are extremely sensitive", Petteri Taalas, secretary-general of the World Meteorological Organization, said today.
The report says a 2C rise will lead to more heatwaves and extreme rainstorms, more people facing water shortages and drought, greater economic losses and lower yields for major crops than 1.5C.
Dr. Joeri Rogelj, of the International Institute for Applied Systems Analysis in Austria and a coordinator of the IPCC report chapter looking at pathways to cut emissions, told DeSmog: "The report provides quite clear messages for fossil fuels in a 1.5°C world, but also highlights that the future out to 2050 looks differently for the various types of fossil fuels". By the year 2030, global human-caused emissions of Carbon dioxide would need to fall by roughly 45 percent relative to 2010 levels.
Fellow author Valerie Masson-Delmotte said: "The report shows that we are at a crossroads". Coral reefs would decline by 70-90 percent with global warming of 1.5 °C, whereas virtually all ( 99 percent) would be lost with 2 °C. The problem with even a slight shift in goals is that the scientific work done in advance of the global talks hadn't provided results for a 1.5°C scenario.
One of the key goals of the accord was to limit the increase in global temperature to well below 2°C relative to pre-industrial levels, and to attempt a more aspirational goal of containing the rise to 1.5°C by the end of the century.
The report's authors take at least one optimistic tone on carbon capture technology, which has so far been too expensive to implement widely but could hold promise for reversing emissions even after the 1.5 degree benchmark is breached. Of the more than 100,000 terrestrial species that have been studied, for example, the number expected to disappear from half their range doubles between 1.5 and 2.0°C.
"We're not on track, we're now heading for about 3 degrees or 4 degrees of warming by 2100", Mark Howden, a climate change scientist at Australian National University, said during an online briefing on Sunday.
"There were doubts if we would be able to differentiate impacts set at 1.5C and that came so clearly".
However, all methods "are at different stages of development and some are more conceptual than others, as they have not been tested at scale", the report warned. But efforts to reduce emissions are lagging in freight, aviation, and shipping, and in industry, he said.