Governments around the world must take "rapid, far-reaching and unprecedented changes in all aspects of society" to avoid disastrous levels of global warming, said a stark new report from the global scientific authority on climate change.
The report issued Monday by the UN Intergovernmental Panel on Climate Change (IPCC), said the planet will reach the crucial threshold of 1.5 degrees Celsius above pre-industrial levels by as early as 2030, precipitating the risk of extreme drought, wildfires, floods and food shortages for hundreds of millions of people.
The planet is already two-thirds of the way there, with global temperatures having warmed about 1 degree Celsius. Avoiding going even higher will require significant action in the next few years.
Global net emissions of carbon dioxide would need to fall by 45 percent from 2010 levels by 2030 and reach "net zero" around 2050 in order to keep the warming around 1.5 degrees Celsius. Lowering emissions to this degree, while technically possible, would require widespread changes in energy, industry, buildings, transportation and cities, the report says.
"The window on keeping global warming below 1.5 degrees Celsius is closing rapidly and the current emissions pledges made by signatories to the Paris Agreement do not add up to us achieving that goal," said Andrew King, a lecturer in climate science at the University of Melbourne.
Even if warming is kept at or just below 1.5 degrees Celsius, the impacts will be widespread and significant.
Monday's report is three years in the making and is a direct result of the 2015 Paris Climate Agreement. In the Paris accord, 197 countries agreed to the goal of holding global temperatures "well below" 2 degrees C above pre-industrial levels and to pursue efforts to limit it to 1.5 degrees C.
The United States was initially in the agreement, but President Donald Trump pulled the country out a year and half later, claiming it was unfair to the country.
"International cooperation is absolutely imperative to limit emissions and therefore global warming and its impacts, as well as coordinating effective and widespread adaptation and mitigation," said Sarah Perkins-Kirkpatrick, a fellow at the Climate Change Research Center at the University of New South Wales. "The next few years will be critical in the evolution of these efforts."
They will also require considerable political engagement globally, as will reducing the amount of carbon being emitted. Despite the report's dire warnings, there is no indication such cooperation will be doable, particularly given the Trump administration's stance on this issue.
"Today the world's leading scientific experts collectively reinforced what mother nature has made clear – that we need to undergo an urgent and rapid transformation to a global clean energy economy," former US Vice President Al Gore said.
"Unfortunately, the Trump administration has become a rogue outlier in its shortsighted attempt to prop up the dirty fossil fuel industries of the past. The administration is in direct conflict with American businesses, states, cities and citizens leading the transformation."