Well, regardless of what our envoy, John Kerry, says, the UN doesn’t believe the COP26 nations have done enough. The graph, below, paints a pretty bleak picture under most scenarios for our biosphere and most forms of animal and plant life. It portends results similar to all-out nuclear war, except in slow motion. Most animal and plant species would either go extinct or their populations would be drastically reduced. For example, if pledges and targets agreed to at the conclusion of COP26 are carried out (and history suggests that this is not likely), at a temperature of +2.1o C above the 1880 mean global temperature, human population might dwindle to between one and two billion people (from the current 7.5 billion).
The graph projects how the various scenarios (shown in color) are likely to reduce greenhouse gas emissions (GHGe, in gigatons) over each decade until the end of the century. The vertical red arrow shows the gap between GHGe in 2030, assuming pledges and targets are met, versus where we should be in 2030 to limit the rise in global mean temperature to only +1.5o C, consistent with 2100. The dotted lime-green line shows the subsequent reduction for each decade in GHGe necessary to be consistent with a +1.5o C increase in the global mean temperature by 2100. This simply won’t happen, according to scientists at Climate Action Tracker.
The blue swath shows the projected upper and lower limits (much like those hurricane track confidence intervals you see on weather maps) of current global policies on GHGe, resulting in a world anywhere from +2.5o C and +2.9o C warmer. The most likely scenario is the purple line showing what happens if we only meet the 2030 target by 2100; we would still be +2.4o C warmer than 1880. Most life would not be able to survive in anything warmer than the “optimistic” scenario of +1.8o C. We are already well into the sixth extinction that started at about +0.7o C (though before 1980 a good portion of the sixth extinction was due to human encroachment and the use of environmental chemicals).
Another important point to consider is that when we talk about average temperatures, some places in the world will be warmer than average and some parts will be cooler. Right now the polar and equatorial regions are warmer and the temperate regions are cooler (though variations occur even within regions). Still, for those of us in the cooler regions, fire, and other weather events are increasing.
So, what will threaten life on the planet? The graphic (as of 2015), below, shows what humanity will face.
For those who question the science, climate projections since the early eighties have been pretty accurate. In fact, most studies underestimated climate impact because population and global national product have been increasing exponentially. Green energy, alone, will not be enough. We have to also cut production; and you know how most people the world over will howl about that.