But they provide little hope the world will rise to the challenge.
The Australian prime minister Scott Morrison says the Coalition will look carefully at the Intergovernmental Panel on Climate Change report which was released on Monday. At the current rate of warming, the world as a whole will reach the 1.5° mark between 2030 and 2052, the report concludes.
For most people, the difference between 1.5°C and 2°C may seem trivial when daily temperatures fluctuate much more widely. Coral reefs would decline by a still unsustainable 70 percent to 90 percent instead of being virtually wiped out under the higher increase.
Chinese scientist Panmao Zhai is a leader of the research.
"Frankly, the more we are prepared to make changes to behavioural patterns that reduce greenhouse gas emissions, the less we would need to rely later on more hard options that we don't yet fully understand like carbon dioxide removal", said Prof Jim Skea. While the United Nations panel says technically that's possible, it saw little chance of the needed adjustments happening. It's called the 2-degree goal.
Temperatures could rise by 1.5 degrees Celsius as soon as 2030 if global warming continues at its current pace and the world fails to take rapid and unprecedented measures to stem the increase, experts warned in a landmark United Nations report on Monday.
While warming of 2C above pre-industrial levels has widely been thought of as the threshold beyond which risky climate change will occur, vulnerable countries such as low-lying island states warn rises above 1.5C will threaten their survival.
"There were doubts if we would be able to differentiate impacts set at 1.5C and that came so clearly".
"The new report from the IPCC has served as a final warning that we must get our act together - now and quickly", said Sunita Narain, director general of the Centre for Science Environment (CSE) while asking the global communities to build a coalition to support the massive transformation required to achieve the 1.5-degree target. The report was authored and edited by dozens of climate scientists from around the world.
The IPCC met last week in Incheon, South Korea to finalise the report, prepared at the request of governments in 2015 to assess the feasibility and importance of limiting global warming to 1.5C. The first stabilises global temperature around the 1.5°C mark with limited overshoot and the second permits temperatures to exceed 1.5°C temporarily before coming back down. He likened the report to an academic exercise wondering what would happen if a frog had wings. "They want Canberra to fix it. Canberra has the power to do that", he said. "It's now their responsibility.to decide whether they can act on it".
"We need to extend this kind of progress on renewables to other areas". Each will have to decide whether to play politics on a global scale for one's own interests or to collaborate to protect the world and its ecosystems as a whole.
The rise has already triggered consequences we are seeing through the seasons such as more extreme weather.
Countries will need to bring down their greenhouse gas to about half of 2010 levels by 2030 and to net zero by about 2050.
The use of cars in Australia is responsible for about 50 per cent of transport emissions, which itself represents the country's third largest source of greenhouse gas emissions at 18 per cent. Switching away rapidly from fossil fuels like coal, oil and gas to do this could be more expensive than the less ambitious goal, but it would clean the air of other pollutants. And that would have the side benefit of avoiding more than 100 million premature deaths through this century, the report said. Limiting global warming to less than 2ºC will hopefully allow ecosystems and animals to adapt to the gradually rising temperatures.