Hundreds of scientists have worked for the last three years to understand just how pressing is the need to limit global warming. The answer - very, very pressing indeed.
Specifically within the next decade, governments and people have to take unprecedented, collective action to limit global warming to 1.5 degree Celsius above pre-industrial (about 200 years ago) temperature.
Scientists and experts from around the world were asked to do so by the UN body on climate change, after the Paris Agreement of 2015.
The report of the Intergovernmental Panel on Climate Change (IPCC) measures the impact of global warming by 1.5 degree versus 2 degree since pre-industrial times.
Speaking to NDTV, one of the report's Indian authors, Aromar Revi, described it as a wake-up call.
The IPCC scientists have concluded that while the effects of a 1.5 degree rise are terrible, it is more acceptable for humans, for other species, for the planet, than the devastation a 2 degree increase will bring.
At current rates, the Earth will be 1.5 degree warmer between 2030 and 2052. That means many of us will be around to see the consequences of our lifestyles, heavily dependent on non-renewables.
The world is already 1 degree hotter. At this level of global warming, India is definitely experiencing climate change, the IPCC scientists say, referring to recent disasters. "People across the world, especially in India, and we can see that in very objective terms, are experiencing the impact of warming. If you take Kedarnath at one end or what happened in Srinagar or Chennai, or recently in Kerala. And of course the very severe drought conditions in many parts of the country. And what we don't understand is that our ecosystems, on which we survive on land and in the oceans, are experiencing this more severely," Revi says.
So what difference can half a degree really make?
At 2 degree, no ice in the Arctic Ocean in summer could be a once-in-a-decade phenomenon. At 1.5 degree the chance is a rarer once-a-century.
At 2 degree, virtually all coral reefs (>99%) would be lost; at 1.5˚ the decline would be a little less at 70-90%.
A 2 degree increase would mean extreme hot days in the mid-latitudes - India will be hotter by 4 degree; that comes down to 3 degree if the rise is at 1.5 degree.
The scientists can say with "high confidence" that the number of hot days is projected to increase, more so in the tropics. That's much of India.
It is a tough ask, the report acknowledges: "The report finds that limiting global warming to 1.5 degree Celsius would require 'rapid and far-reaching' transitions in land, energy, industry, buildings, transport, and cities. Global human-caused emissions of carbon dioxide (CO 2) would need to fall by about 45 percent from 2010 levels."
This should happen by 2030, the report says, reaching 'net zero' around 2050. The danger is not just from carbon dioxide but now also from methane, black carbon (soot) and other emissions, it says.
IPCC scientists say we are already experiencing the climate change effects of temperatures one degree higher than about 200 years ago, when the industrial revolution began, riding on coal as the source of energy.
For India, coal remains a challenge.
On one hand it's available in abundance and coal-produced thermal electricity can pull millions out of extreme poverty. On the other, as the scientists point out, it means "very, very severe challenges of air pollution in many months of the year." The Centre has already failed to meet its own deadline of 2017 to start reducing emissions from existing thermal power plants.
The impact of global warming will be felt on mega cities, like Delhi-NCR and Mumbai, high mountains, small islands and particularly coastal regions as sea levels will rise.
Joyshree Roy, another contributing author of the report from India, says action has to be taken starting immediately over the next decade and that it is not impossible to stick to the 1.5 degree redline.
Revi calls it an opportunity for India, drawing a similarity to the 1960s Green Revolution response to the agri-crisis then. Except this time, it's not just agriculture, but each and every sector has to start changing rapidly and soon.
"Bangalore, Delhi... Indian cities already experience the urban heat islands, past the 1.5˚ above the global average. Cities will bear the brunt and have some of the most vulnerable populations," says Revi.
It's an opportunity that could translate into jobs, the scientists explain. From making a resilient economy based on a rising share of renewable energy. The Prime Minister's Awas Yojana to build 20 million homes over the next few years, they say, could be more energy efficient both in the way these are built and used to reduce cooling and heating; the bureau of energy efficiency has laid down rules for commercial buildings but these should be extended to homes.
Bulbs will have to be all LEDs, not even CFL, in every last house that gets power. There should be a bigger shift towards public transport and electrification of vehicles. And of course, there should be more afforestation and re-forestation.
Failure to act and crossing the 1.5 degree mark will mean more poverty, worse air pollution and food and water shortage, apart from species suffering or even dying out. However, in India, one of those involved says, "the challenge is in imagination, coordination, putting resources in the right place and building capacities. It is still stuck in a very old way of looking at these things. This is where a shake-up is required".
The report calls for collective efforts globally. Notably, US experts also backed today's report despite US President Donald Trump's actions against climate change mitigation efforts, like pulling out of the Paris Agreement and pushing for coal-produced power.
The scientists say they have studied and documented the impact and now it's up to governments to decide what to do.
The estimated cost for humans to adapt to rising global warming is a trillion dollar agenda, mainly to reorganise the energy sector. That seems like a small price to pay in the light of the IPCC report.
(Chetan Bhattacharji is Managing Editor at NDTV)
Disclaimer: The opinions expressed within this article are the personal opinions of the author. The facts and opinions appearing in the article do not reflect the views of NDTV and NDTV does not assume any responsibility or liability for the same.
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