Approved by the IPCC in South Korea on Saturday ahead of COP24 in Poland in December, Global Warming of 1.5°C was produced by 91 authors and reviewers from 40 countries. They tell how global warming of more than 1.5°C will be a huge risk and to prevent it we ... that's the whole world ... must halve our emissions in 10 years.
"There were doubts if we would be able to differentiate impacts set at 1.5C and that came so clearly".
Limiting warming to the lower goal is "not impossible but will require unprecedented changes", United Nations panel chief Hoesung Lee said in a news conference in which scientists repeatedly declined to spell out just how feasible that goal is.
He said: 'We know what is needed to limit global warming to 1.50C and we can do it relying mostly on proven technologies such as decisively scaling up renewable energy and halting deforestation.
The consequences of a 1.5°C rise include extreme temperatures in many regions across the world, increases in frequency, intensity and/or amount of heavy precipitation, and an increase in intensity or frequency of droughts in some regions.
Starting in 1994, a central aim of the UN's climate change efforts (the Framework Convention on Climate Change, or UNFCCC) was to stabilise greenhouse gas concentrations at a level that would "prevent unsafe anthropogenic interference with the climate system".
The conclusions are based on an analysis of more than 6,000 climate separate studies. Keeping the rise in temperature to 1.5C would mean sea levels by 2100 would be 10cm lower than if the warming was 2C, the likelihood of an Arctic Ocean free of sea ice in summer would be once a century rather than at least once a decade, and coral reefs would decline by between 70 and 90 percent instead of being virtually wiped out.
Stephanie Pfeifer, chief executive of the Institutional Investors Group on Climate Change (IIGCC) which represents investors with trillions of pounds of assets under management, said the report showed limiting global warming to 1.5C is what was needed. Global net emissions of carbon dioxide would need to fall by 45 per cent from 2010 levels by 2030 and reach "net zero" around 2050.
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Some 164 people were arrested, most for demonstrating on the Capitol steps, 14 for disrupting the Senate's roll call vote. I testified with five people foremost in my mind: my mom, my dad, my wife, and most of all my daughters".
Chandra Bhushan, the deputy director general of Centre for Science and Environment (CSE), says, "Though it will be very hard in the current global economic system to limit warming to 1.5°C, it is not impossible". The report also waded into murky questions about ethics and values, stressing that governments must address climate change and sustainable development in parallel, or risk exacerbating poverty and inequality.
The report makes it clear that climate change is already happening - and what comes next could be even worse, unless urgent global political action is taken.
Neither Premier Ford nor Mr. Kenney have yet said what policies they would employ to cut emissions, or whether they support Canada's objective of reducing greenhouse gas emissions by 30 per cent below 2005 levels by 2030 - a commitment made under the Paris accord. Adding another a half degree Celsius on top of that - the looser global goal - essentially means a different and more challenging Earth for people and species, said another of the report's lead authors, Ove Hoegh-Guldberg, director of the Global Change Institute at the University of Queensland, Australia.
Average global temperatures are now 1C above pre-industrial levels, and are likely to increase 1.5C between 2030 and 2052 under current trajectories, the report says.
In the United Kingdom, where existing legal targets require 80pc cuts in emissions by 2050, the government is under pressure to strengthen action on climate change.
Meeting the 1.5C target would keep the global sea level rise 0.1 meter (3.9 inches) lower by 2100 than a 2C target, the report says. The world now pumps more than 40 billion tons of Carbon dioxide into the atmosphere each year; the IPCC calls for that number to be cut by more than 1 billion tons per year over the next decade.
Hong Kong's climate action plan, published previous year, only pledges a 26 to 36 per cent cut by 2030 from 2005 levels.
The Greens recently tabled a motion at City Hall that the council should consider preparing a climate change adaption strategy.