Thursday, June 20, 2013

We Live on Land, Not in the Oceans

Judith Curry writes:
Exactly how does focusing on the mean surface temperature miss the point? Global warming is pretty much defined in context of the mean surface temperature. People live on the surface, not in the ocean below 700 m.
OK. But people don't live on the surface of the ocean either, which is warming much slower than is the surface of the land.

The 30-yr trend of CRUTEM4, which only includes land measurements, is 0.28°C/decade -- 1.5°F of warming in just three decades.

The 15-yr trend is 0.11°C/decade.

By contrast, the 30-yr trend for HadCRUT4, which measures the entire surface, land + ocean, is 0.17°C/decade. The 15-year trend is 0.05°C/decade.

Clearly land is warming much faster than the ocean. Where does this fit in the calculations?

It seems to me the real question is: does the Earth system have an energy imbalance? If so -- if more energy is coming in than leaving at the top of the atmosphere, then there will be warming. Sometimes it will be mostly in the oceans, sometimes larger on land, almost always melting ice and raising sea level.

That's the real question. And if it's a mystery why the ocean has lately been taking up more heat than it was before, how is that comforting? What other unexpected and unforeseen changes lie in our future? Will the next one be to our benefit, or our detriment?


Anonymous said...

Yes, I agree completely. Getting people to recognise that it is fundamentally about an energy imbalance and not simply about surface temperatures is important. Our climate is not only about the land and if an energy excess persists, then surface temperatures will have to continue rising at some point unless our understanding of fundamental physics is horribly flawed.

TheTracker said...

Very true.

tonylearns said...

if a lot of this extra energy is stored in the ocean it seems to me that could mean that could increase the time it takes for that heat to impact surface and atmosphere temps.
That might be good news in terms of giving us more time before certain impacts of ACC become stronger, but bad news for mitigating more longer term effects. Do we have much knowledge on the factors that influence these time scales?