|% in the graphic above should be degrees C|
Regular readers will know that I've pointed out again and again that renewables (wind, solar and CSP) costs keep on falling, and that they are already below the cost of electricity from new coal power stations, will soon be below the cost of existing fully depreciated and paid off coal power stations, and are catching up fast with gas. Battery costs will halve or more than halve over the next 5 years: this will make battery storage cheaper than peaking power gas or gas "firming". Electric cars will have a sticker price equal to or below petrol driven cars by 2022--they are already cheaper to run. So what's going to happen is that by the mid 2020s, carbon emissions are likely to be falling fast, just because power generation and transport produce something like 70% of world CO2 emissions.
But the problem is this: world temperatures are rising by 0.2 degrees C per decade, and will go on doing so until emissions fall by 90% or more. Remember, it's not enough to have emissions peak, because the level of CO2 in the atmosphere will continue rising until emissions fall below the natural processes which slowly remove CO2 from the atmosphere. And that means that temperatures will go on rising too--until CO2 emissions have fallen enough that the level in the atmosphere starts to fall as well.
Also, there is the terribly frightening risk that methane clathrates melt. This is methane frozen on the sea bed or in the tundra, which may start to melt and be released into the atmosphere as temperatures rise. Eventually methane decays to CO2, but over its first 20 years in the atmosphere, it is 84 times as potent a greenhouse gas as carbon dioxide.
We have at least 2 decades where, even though CO2 emissions will be falling, they won't have fallen by enough for the accumulated CO2 in the atmosphere to level off and start declining. So global temperatures will rise by at least another 0.4 degrees C. Even if we get to 100% green electricity generation and 100% green land transport, important CO2 emissions sources will remain: iron and steel, cement, shipping, air transport, land and forest clearing and burning. There are solutions here too, but nowhere near enough is being done to get them activated.
Some accuse me of being an optimist. They say I will stop the political and community efforts to reduce CO2 emissions because I am very optimistic about the take up of green electricity generation and transport over the next 20 years. But transitioning those sectors to a carbon-free state won't be enough, even assuming the transition isn't delayed by greedy billionaires keen to keep their oil and coal businesses going until the planet roasts. There is no place for complacency. We have to reduce CO2 emissions by 95% or more by 2050, preferably by 2040. The sooner the better. And our elected representatives will only start feeling the urgency if we make them, if we push them to encourage moves away from fossil fuels in every industrial and agricultural process in our economy.
Believe me, the consequences we have already seen from the 1.2 degrees rise since before industrialisation will be an order of magnitude smaller that the consequences we will see at 2 degrees or higher. So in 2017, spread the word, show that it's doable, but that we have to keep on pushing, and remind politicians that infantile day-to-day food throwing and tantrums is all very well, but we expect them to enact policies which encourage a shift to 100% carbon-free economies, not in some my-little-pony far off future, but now.