Among the three of us, we have 15 decades of high-level experience in climate science, policies, and actions, and we have never been more alarmed than we are at this moment. The United Nations has just officially declared that the world has failed in limiting global warming to a safe level. During the last decade, heat-trapping pollutants nearly doubled the rate that heat is being added to the planet—a rate that will push temperatures across the 1.5°C threshold in five years or less and breach the first barrier of the Paris Agreement. This will further destabilize natural climate systems and amplify weather extremes, which are already costing the world economy more than $ 2 trillion annually. At the current rate of warming, the global temperature is likely to cross 2°C in about 15 years, the outer limit of the Paris Agreement, taking us into a climate not witnessed by homo sapiens, ever.

High altitudes in the Tibetan-Himalayan region and the Alps are already warming at two to three times the global average (which may be implicated in the recent Nepal-Tibet floods that left 1,400 confirmed dead and 5,000 missing). Other disastrous impacts of reaching 2°C include the transition of the Amazon from a forest into a savanna. The health impacts could be the worst of all. At 2°C, heat deaths in 2050 could reach a staggering 2 billion in a worst-case analysis by actuarial experts at Exeter University.

If that weren’t bad enough, a new scientific study raises the possibility that the current rate of warming, if continued, could eventually shut down the ocean current called the Atlantic Meridional Overturning Circulation—AMOC. The Gulf Stream is a major part of this vital ocean current, which plays a dominant role in winter weather over North America and Europe. Worryingly, AMOC is already slowing down.

We know of no other measures of thinning the heat-trapping blanket to provide the rapid cooling needed to allow us to survive and thrive.

At today’s rate of warming AMOC could begin to collapse at warming as low as 2°C, which could be crossed by the time today’s infants are in college. Impacts would be punishing, stranding heat in the already too hot tropics, while robbing northern countries of heat now transported north to keep temperatures temperate, leading to bitter winters. If AMOC collapses, currently a low-probability event, it could trigger massive forced internal and international displacements, ushering in the world’s largest crisis of forced migration ever.

Crossing 2°C will trigger other irreversible impacts too, further amplifying warming through the loss of sea ice and glaciers. The depletion of ice and snow will make the planet darker, resulting in more absorption of incoming solar radiation, amplifying warming by 25% or more.

The good news is that we can avoid this fate if we cut the rate of warming quickly—by 50% within 15 years, which is feasible in two parts.

First, we need to cut the super pollutants of climate. These include hydrofluorocarbons (HFCs), methane, lower-atmosphere ozone, and black carbon soot from diesel and cooking smoke. These short-lived climate pollutants are called super pollutants because they are tens to thousands of times more potent than carbon dioxide in heating the planet and are currently contributing more than half of the warming the planet has........

© Common Dreams