Jim
I'm not sure it is "technically possible" to avert "a catastrophic collapse with vast human suffering and population loss". In fact those unfortunate enough to reside in the Mid-East have been experiencing this for some decades.
Climate change may have been responsible for the initial instability in Sudan and Syria, but most of the blame can be placed on one government's belief that so called fossil fuels were running out, and that the only way to assure continued world dominance was to control the sources of this dwindling, finite resource.
Kid gloves were removed to reveal the steel fist, diplomacy and good will were replaced with reckless displays of military might and the fearful acquiescence that ensued. France and Germany were expected to accept the gutting of major industries by foreign court decisions and trade rulings. Russia was driven from the playing field after Ukraine's sponsored coup, Crimea's homecoming, and NATO's inexorably tightening noose.
Europe suffers from both sanctions and counter sanctions as the flood of Syrian refugees is blamed on Putin and Assad rather than the Western armed and Saudi financed ISIS that drives them from their homes. The Saudi's pulled the plug on oil prices to break Russia, just as was done in the 80's to destroy USSR, however this time around Canadian tar sands, American frackers and South American oil producers are feeling the brunt of the pain.
Russia's unexpected military prowess and financial resilience are causing problems, but no one can long stand against The West.
The sad thing is that oil and gas are of abiotic origin, and as such are about 2 orders of magnitude more prevalent than TPTB believed when they began their quest for energy domination. Oil isn't running out and natural gas is so abundant that it's hardly worth the cost of transportation. Millions dead, tens of millions driven from their homes, all to secure access to forms of energy that are increasingly a glut on world markets.
Solar,wind, batteries and a decent distribution grid. If a tiny percentage of what is spent on armament was diverted to these, everyone would have their energy needs met, everyone would live in a cleaner, safer,world, and oil producing regions wouldn't fear bombing, assassinations and coups financed from across the globe.
Climate change is and will be an enormous, growing problem, but if we eliminated the military adventurism of those attempting to monopolise energy production, perhaps we could then work to mitigate the damage already done and end our continuing assault on Gaia.