Real Global Temperature Trend, p21 – Science is ruthless. We have ‘about zero’ years of emissions to stay below 1.5 degrees

That is if you correct for one important piece of scientific criticism to the below graph. But even if you prefer to ignore what may seem the nitty gritty of climatology and accept a maximum global carbon budget of 8.9 years one conclusion should resound across our planet: The time of coal is over.* Yesterday. We cannot build any new coal lock-in infrastructure – and we have to shut down all the existing coal plants, and stop all the existing coal transport – both exports and imports.

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Real Global Temperature Trend, p20 – Combining thermal inertia & carbon cycle inertia: 1 decade extra warming after emissions stop

Apart of course from the amount of greenhouse gases we keep pumping into the atmosphere, there are mainly three factors that determine the amount of warming we will experience in the near future: CO2 climate sensitivity, ocean thermal inertia, and carbon cycle inertia. Here we try to make better sense of their combination.

Climate inertia atmospheric warming
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Real Global Temperature Trend, p19 – There is hot, hotter, hottest – and 2016: dangerously close to pre-industrial +1.5 degrees…

The 19th edition of our global temperature trend series is ‘just a graph’. That is because we are still overwhelmed by Break Free 2016. And because some graphs simply speak for themselves.

The progression of the 2016 hottest year global temperature record does that like no other. It shouts:

2016 hottest year on record - graph
Comparing hottest years. 2014 broke 2010. Then 2015 broke 2014. Then suddenly in early 2016 we almost crossed a line we’re not supposed to cross for the rest of the century.

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Real Global Temperature Trend, p18 – Now how high is climate sensitivity? Here’s the answer of the world’s 15 leading climate experts!

If you have any affinity with climate science, this should interest you – probably a lot:

Piers Forster, James Hansen, Gavin Schmidt, Alan Robock, Michael Mann, Ken Caldeira, Stefan Rahmstorf, Chris Forest, Gabriele Hegerl, Hans Joachim Schellnhuber, Jonathan Gregory, Drew Shindell and Andrei Sokolov share their thoughts, and gut feelings, on climate sensitivity.

[Update! Shortly after publishing this piece we've received the answer of two other leading climate sensitivity experts, Mark Zelinka and Trude Storelvmo. You can find their thoughts on ECS value in the update at the bottom of this article.]

climate sensitivity estimates
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Real Global Temperature Trend, p17 – Climate System Thermal Inertia is lower when you don’t assume CO2 flatline

Oceans, oceans, oceans. You thought the atmosphere was complex? Well, just take a look at the oceans. Oddly shaped features with disturbing cycles and conveyor belt currents. Home of the octopus, the blue whale and a Mariana Trench full of complicated science.

ocean CO2 climate inertia & ocean thermal climate inertia
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Real Global Temperature Trend, p16 – Climate System Thermal Inertia: Trend Line = 0.6C higher than observed temperatures show

In part 16 of our temperature trend series we take a better look at one of the main reasons almost everyone still underestimates climate urgency: ‘Thermal inertia’ of the climate system – a delay between the moment of emissions of CO2, and the moment the (majority of) inevitably resulting atmospheric warming manifests itself – a time lag of decades, with very large implications.

Ocean warming graph - interacting with the atmosphere, causing climate inertia
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Real Global Temperature Trend, p15 – 2016-2020 global forecast: 5-year average temperatures above 2015 record, despite La Niña

It’s raining climate records since late 2014. That has increased to a proper storm from October 2015 – the first month to show global temperature anomalies of more than 1 degree above the 1951-1980 climate average (so higher still above pre-industrial(!)). And if April 2016 too will have an average global temperature deviation of at least about 0.9 degrees above 1951-1980 climate average (and it will likely be higher) then the world will have had 12 consecutive monthly temperature records.

Take a minute to think about how insane that really is: Each and every month breaking the monthly temperature record in a data range that goes back to at least 1880. So much for ‘natural climate variations,’ right?

2014 was the then-hottest on record, which was broken by 2015. And despite the fact that La Niña conditions are developing and East-Pacific (see graph below) ocean temperature anomalies already peaked in November 2015 – our guess is that 2016 will break 2015′s global temperature record.

La Niña forecast 2016 - IRI ensemble graph
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Real Global Temperature Trend, p14 – Just one more to go and world has 12 monthly records in a row – temperature jump +0.2 degrees

Yes, if you would extrapolate the global temperature “trend” line from early 2015 to early 2016, you would look at a 20 degrees Celsius warming over the century.

March broke the record of all Marches. February broke the record of all Februaries. January broke the record of Januaries. And if April too would break the record of all recorded Aprils before – then we would have 12 such monthly temperature records in a uninterrupted row(!!)

NOAA global temperature graph March 2016
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