"Every extra bit of warming matters, especially since warming of 1.5ºC or higher increases the risk associated with long-lasting or irreversible changes, such as the loss of some ecosystems", says Hans-Otto Pörtner, Co-Chair of IPCC Working Group II, one of three working groups comprising the report, in a press statement.
That is the tough-love conclusion of the U.N.'s Intergovernmental Panel on Climate Change, or IPCC, in a major consensus report released Sunday evening after days of discussions last week between scientists and government officials meeting in South Korea.
Global temperature is now rising 0.2C with each decade, and it is estimated we will reach 1.5C by 2040. Rather, it states with a high degree of confidence that "human activities are estimated to have caused approximately 1.0°C of global warming above pre-industrial levels, with a likely range of 0.8°C to 1.2°C". Currently, however, the world is on track to see between 2.7 and 3.4 degrees of warming, the IPCC has said.
Economies would have to shift away rapidly from burning coal, oil and gas and invest heavily in renewable energy. 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 feasibility of solar, wind and battery storage has improved significantly in recent years, which could signal the system is transforming, the report says.
The study was urgent because CO2, the main greenhouse gas, reached record levels in the atmosphere a year ago, and current pledges to cut emissions under the Paris Agreement would lead to warming of about 3 deg C.
Countries must take "unprecedented" action to slash carbon emissions to zero by 2050 and limit risky global warming, a key report has warned.
"Let's not forget that Australia accounts for just over one per cent of global emissions, so there are a lot bigger players than us out there impacting on these arrangements", the PM said.
When the target was put into the Paris Agreement, relatively little was known about the climate risks that would be avoided in a 1.5C warmer world compared with a 2C warmer world, or about the action needed to limit temperature rises to that level.
The IPCC report is undeniably grim, but its authors state that the 1.5°C target can still be met if unprecedented, wide-ranging action is taken straight away.
The government has been urged to strengthen United Kingdom climate targets and action, to reduce the severity of climate impacts, ranging from extreme weather to rising seas. But it means ensuring temperatures don't rise more than half a degree.
For example, according to IPCC, by 2100 global sea level rise would be 10 cm lower in case of a 1.5°C rise compared with a 2°C rise.
"Large quantities of current gas plants will need to be retired early, while those under construction or in planning stages must be reconsidered immediately as they are not compatible with the 1.5-degree future", Chen said.
"The coal industry has no role in a climate-stable world", said Jan Erik Saugestad, chief executive officer of Norway's Storebrand Asset Management, which oversees US$88 billion. To have at least a 50/50 chance of staying under the 1.5C cap without overshooting the mark, the world must, by 2050, become "carbon neutral", according to the report.
Delaying action on climate change "is something that is explicitly contradicted in the report", he told the Thomson Reuters Foundation. Any additional emissions would require the removal of Carbon dioxide from the air. So far, Prime Minister Scott Morrison has said that he's "not going to spend money on global climate conferences and all that nonsense", while Deputy PM Michael McCormack described the landmark United Nations warning as "some sort of report" and said Australia will "absolutely" keep relying on coal-fired power.
Coal power would also need to be reduced to nearly nothing.