Tuesday, 17 June 2014

By 2100 what will our world be like?

Here is my dad on his 86th birthday earlier this month, coincidentally 86 years before 2100. Neither he nor I expect to live that long, but today's babies should. So what will the world be like on their 86th birthday?

Well, a trip to the seaside should be a bit quicker.

In the 2013 IPCC report predicted sea level rises are between 0.7 and 1m by 2100, as can be seen in this graph. These IPCC figures have been criticised as being too conservative, and it looks like the critics were right. (See below). To be fair, the IPCC report does say that predicted ice sheet melting has significant uncertainties.

Although according to this article on the Climate Code Red website new data shows that the expected rise in sea levels of about 1m will actually be between 3m to 5m by 2100. The ice is melting quicker than expected.

What about the temperature? 

We all know it will be hotter, but how much? Once again I turned to the IPCC for this graph. There are four different scenarios, but even the most optimistic shows temperatures still rising throughout my lifetime until they level out mid century.

So what are these scenarios? 
Well this is from the IPCC report.

Frustratingly they don't actually say it in plain English, but to summarise - only the lowest emission scenario, with aggressive cuts in fossil fuels, keeps global average temperatures below the 2°C maximum rise agreed at Copenhagen. The worst scenario can best be described as 'business as usual' and will result in a 4°C rise by 2100 for our baby. 

I've found more detail on RCP2.6 so here's another graph taken from “RCP2.6: exploring the possibility to keep global mean temperature increase below 2°C” – Van Vuuren et al 2011.

The biggest snag I can see with this scenario is that half of all energy production has to be with Carbon Capture and Storage, which is very experimental technology. Fossil fuels are also still a massive part of the mix. Renewables seem to be no different than in the baseline trend, while they could be expanded hugely with the right political will, especially now that solar panels are competitive with fossil fuels. 

When I investigated scenario RCP8.5, I was expecting even worse news. I was pleasantly surprised by "RCP 8.5 - A scenario of comparatively high greenhouse gas emissions" has the following graphics.

These graphics show a completely different mix of fuels.

A bit more research gets me to see the obvious. The IPCC report is not interested in how we make the changes, just how the climate changes under different forcing scenarios. You have to look at other reports which suggest different ways of achieving the forcing scenarios. Some authors rely on CCS others renewables, but I conclude that the IPCC 2013 report does not even include a Green scenario as a possibility. This is not acceptable. We in the Green Party will make sure that today's babies grow to old age in a truly sustainable world.

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