Thursday, February 22, 2018

Very high risk of more than 1.5 degrees

5 year moving average of the global temperature anomaly
relative to to 1901 to 2000 period
Source: NOAA



A leaked U.N. climate report sees  a ‘very high risk’ that the planet will warm beyond the key limit of 1.5 degrees C.

A draft United Nations climate science report contains dire news about the warming of the planet, suggesting it will likely cross the key marker of 1.5 degrees Celsius, or 2.7 degrees Fahrenheit, of temperature rise in the 2040s, and that this will be exceedingly difficult to avoid.

The draft document states that there is a “very high risk” of the planet warming more than 1.5 degrees above the temperature seen in the mid- to late 19th century.

Maintaining the planet’s temperature entirely below that level throughout the present century, without even briefly exceeding it, is likely to be “already out of reach,” it finds.

[Read more here]

Global temperatures are rising, on average, by about 0.2 degrees C per decade.  If we can convert all electricity generation to renewables/nuclear and if we can switch all cars and lorries to electric engines, we could slash CO2 emissions by 70%.  We would still need to find a better way to make steel and cement, we would need to power our jets with bio fuel, and we would have to stop clearing and burning forests, but we'd be well on the way to reducing emissions to zero.

I think EVs will take over from ICEVs much quicker than the consensus now holds, as I've said before.  The costs of batteries, and therefore of EVs, will fall so fast that by the mid 2020s, no more ICEVs will be sold.  That shift will be encouraged and enforced by governments trying to reduce air pollution.  But it will take the next 10 or 15 years for the whole vehicle fleet to be replaced by EVs, so even my optimistic forecasts won't get to zero transport emissions for 20 to 25 years.

New wind and solar farms are cheaper than new coal in most places in the world, and although in some locations new wind and solar now cost less than the operating costs of coal, the practicalities of replacing a whole generation fleet with renewables mean that it will also take another 20 or 25 years to get to 100% green electricity.  During that time, global temperatures will rise another 0.4 or 0.5 degrees.  Global temperatures have risen about 1 degree C from the 1800s.  So that means we will have reached the 1.5 degree increase at about the time we finally stop burning fossil fuels for energy and transport.  We will have to get to zero CO2 emissions by 2040 is we are to stop global temperatures rising more than 1.5 degrees. 

We might make it.  Might.

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