Temperatures have already risen by 1C in the past 100 years, leaving just half a degree more before the limit is reached.
Scientists have long warned that mankind should limit warming to 2 deg C to avoid catastrophic climate change. "However, time is running out, so we must capitalize and build on the solutions available today".
The goal posts for the Paris Agreement have moved. These heat-trapping gases are the byproduct of industrial processes such as refrigeration and can be eliminated from those processes by re-engineering.
That benchmark is lower than the one set by the global Paris Agreement, which aimed to prevent the planet from warming by 3 degrees Celsius.
Clearly, that deceivingly small half-degree difference has the potential to bring about significantly worse effects.
In reality, it seems far more likely that the world will "overshoot" the 1.5 degree mark, causing irreversible harm.
To date, there's no overarching consensus on what the budget should be-which creates uncertainty about how much time is left, under current emissions trajectories, before the clock runs out on the Paris climate targets.
By 2050, humanity would need to cut its net emissions to zero.
Doing that would require an immediate, massive, coordinated transformation of the global economic system - especially the energy system. But that number is an average of temperatures all over the globe, so some places will become significantly hotter. The likelihood of an Arctic Ocean free of sea ice in summer would be once per century with global warming of 1.5 degrees Celsius, compared with at least once per decade with 2 degrees Celsius. These factors could trigger huge migrations of people and mass extinctions of animals.
Coral reefs will also be drastically affected, with between 70 and 90% expected to die off, including Australia's Great Barrier Reef.
And, of course, Trump has been trying to slash carbon regulations instead of strengthening them.
The report further revealed that global warming has already had an effect in regions across the world. Average temperatures rose by 0.12 of a degree per decade from 1885 to 2017.
"The next few years are probably the most important in our history", warned Debra Roberts, Co-Chair of IPCC Working Group II. President Macron's One Planet Summit followed in NY during Climate Week, bringing together leaders of finance who were optimistic that managing climate risk is not only possible, but an exciting challenge that would also be profitable as new industries arise to do the most important work the world has ever demanded.
There are financial estimates of the damage, too. Coral reefs would be devastated-about 70%-90% would be lost with a 1.5 degree increase; nearly all the world's reefs would be eviscerated if average temperatures rose by more than two degrees.
The US Environmental Protection Agency, which has an official position that climate change is harmful to public health, thanked the "hard work of the scientists and experts" but said it did not "formally endorse specific findings presented by the authors". "We must reduce emissions as quickly as possible to keep 1.5 deg C of warming within reach", said Mr Andrew Steer, president and chief executive of the Washington-based World Resources Institute.
Of course, these two methods will need a lot of global political engagement in an increasingly short time, and with certain big player administrations like Trump's now stalling worldwide cooperation, that 2030 deadline is looking more and more ominous. But right now, they aren't cost-effective or efficient enough.
The report's full name is Global Warming of 1.5 °C, an IPCC special report on the impacts of global warming of 1.5 °C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty. This latest report shows that the need for action is more urgent than ever.
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