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No warming for 16 years?

If you're only looking for evidence of warming in our atmosphere you're missing 95 per cent of the actual warming of our planet. Dr Karl sets the record straight on claims global warming is over.

In September 2013, the IPCC (that's the Intergovernmental Panel On Climate Change) released a Preliminary Report. It was called Climate Change 2013: The Physical Science Basis.

Well, this preliminary report was somehow misquoted and misinterpreted by some of the news media — so let me try and put the record straight.

First up, you should realise that the IPCC itself does not directly monitor the climate, nor does it directly carry out original research. No, this scientific body (established in 1988) is made up of thousands of climate scientists who review the research and then write the reports.

Even before this report was released, some of the news media (such as the Daily Mail in the United Kingdom) recklessly claimed that this latest IPCC report revealed that global warming was over — and that in fact, the world was now cooling. This was very wrong.

For one thing, nine of the 10 hottest years on record have happened in the last decade.

So I'll discuss just two facts — how carbon dioxide causes global warming, and where this heat is going.

Burning fossil fuels gives us heat, which we then convert into energy such as electricity, or the motion of cars and jets. But burning fossil fuels also releases carbon dioxide into the atmosphere. As a result, since the beginning of the Industrial Revolution, carbon dioxide levels have increased from 280 parts per million (ppm) to about 400 ppm. About one third of the carbon dioxide goes into the oceans, but two thirds remains in the atmosphere.

In the atmosphere of our planet, this carbon dioxide upsets a previously stable balance (heat in versus heat out). This balance is between the amount of heat energy entering the atmosphere from the Sun, and the amount of heat energy leaving the surface of our planet and heading out into the blackness of space.

Carbon dioxide behaves a little like a semi-silvered mirror. It has the effect of 'reflecting' some of the heat energy that leaves the surface back down to the surface again. It's not a huge amount of heat — for each square metre of the Earth's surface, there's about half a joule of the energy trapped each second, or if you like, half a watt of power.

The trouble is, the surface of our planet has many many square metres. So that extra heat reflected back down to the ground is roughly equivalent to exploding a few hundred thousand Hiroshima-sized nuclear weapons in our atmosphere — every day. Or to use another odd unit, that extra heat could boil dry all the water in Sydney Harbour a couple of times each day.

However, all that the energy is not concentrated on Sydney Harbour, but instead, it's spread out across the surface of the globe.

Now here is a fact that not many people appreciate.

Only about 2.3 per cent of this extra heat energy goes into heating the atmosphere. Another 2.1 per cent goes into the the continents. Then there's some bits and pieces — 0.9 per cent into the glaciers and ice caps, 0.8 per cent into the Arctic sea ice, 0.2 per cent into the Greenland ice sheet while another 0.2 per cent of this extra heat energy warms the huge Antarctic ice sheet. So if only 2.3 per cent of the extra heat energy warms up our atmosphere, and another 4.2 per cent goes into bits and pieces, where does the other 93.5 per cent go?

Into the oceans.

The overwhelming majority of the heat trapped by the extra carbon dioxide in our atmosphere enters the oceans.

Since 2007, we have been monitoring the oceans with small drifting oceanic probes — ARGO probes. Today, there are some 3,600 of these robotic probes in the oceans of the world. They continuously float up and down, rising to the surface and then diving down to a depth of 2 kilometres on a roughly 10-day cycle.

These ARGO probes have measured the heating of the oceans caused by that 93.5 per cent of the heat energy reflected back down by the carbon dioxide in the atmosphere. It turns out that about two thirds remains in the upper ocean between the surface and a depth of 700 metres, while the remaining one third of that heat energy goes deeper into the ocean — between 700 and 2000 metres.

What effect will this have? At this stage, we simply don't know.

So remember this — if you look for evidence of global warming only in our warming atmosphere, you're missing over 95 per cent of the actual warming of our planet. And that could spell a whole sea of troubles …

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