Thread by @Gergyl

What is this about? Don't know? Maybe you should.

Data from: ceres-tool.larc.nasa.gov/ord-tool/jsp/E…

What about this, for the whole planet? Properly interpreting and understanding this dataset is tricky.

This is actually seasonally adjusted (not anomaly from an adopted climatology, which is what is labelled 'deseasonalised' on the CERES site):

Rocky planets everywhere are radiation balance engines. Their surface temperature – or atmosphere temperature, if they have one – depends on a fine balance between incoming radiation from their star(s) and outgoing heat radiation to space, mostly in infrared ('longwave').

That is us, Earth and our Sun. We now measure this radiation balance, pretty accurately, from satellites, like this, below.

(Why 'top of atmosphere'? Because that takes the complexity out of it – whatever complex stuff the atmosphere is doing is already done, for these numbers.)

Those traces are not equal; haven't been for decades – absorbed incoming solar radiation exceeds outgoing heat radiation to space, by a lot. What's more, they're diverging.

That ought to worry us (I think terrify us), but somehow it doesn't. Why does it matter?

The difference between those two, the net (inward) radiation flux, looks like this, plotted as the 12-month moving average. It's been trending higher, with a suggestion of recent acceleration.

(Trend shown is for the underlying data. There's no reason to expect it to be linear.)

…Which of course is what we plotted up above, showing the full seasonally adjusted monthly data (rather than the moving average). For scale, two watts per square metre over the whole Earth's surface is the equivalent of about 1 trillion electric radiators, operated continuously.

Two watts per square metre spread over the 510 million square kilometres of the Earth's surface is about one million gigawatts, 1 petawatt, or a trillion one-kilowatt domestic radiators. Where does all that excess heat go? Into heating up the planet of course – 'global heating':

...Into heating the atmosphere, into heating the land surface, into evaporating more water (because hotter air holds more of that), and into melting ice, but mostly into heating up the oceans, because the thermal capacity of water is very great.

About 93% of it goes to heating the oceans, most of that (at the moment) into heating the shallow ocean – down to about 300 m depth: essd.copernicus.org/articles/15/16…

What's more, we can check the (also now carefully measured) ocean heat uptake against the satellite-measured top-of-atmosphere radiation imbalance, and they match, near enough. This ain't some giant mistake.
agupubs.onlinelibrary.wiley.com/doi/10.1029/20…

None of which will be news to those following along at home for about the last 30 years, but maybe it is to others. But there *is* a new thing here -- absorbed solar radiation has been increasing a lot over the last decade, and still is ... sharply:

That's never really been part of the story. Greenhouse heating is supposed to be all about trace gasses (CO2!) blocking outgoing heat radiation (it is). No one mentioned *increasing incoming radiation*. What's this from?

Increased solar output? Nope. That *is* higher at the moment – there's an 11-year cycle – but only by a tiny bit (graph same scale):

It's because the Earth is *absorbing more sunlight* (and reflecting less). Because there's less ice (especially sea ice) to reflect it? Yes, but that isn't most of it.

Mostly it seems to be due to less clouds, that probably due to less atmospheric aerosols (particulates), that due to less pollution from fossil fuel burning (ironic, this is). But about there agreement falls apart. You see mainstream climate science doesn't (yet) think so...

So to this – James Hansen, the 'father of modern climate science', screaming from the rafters (with others), and Michael Mann, also no slouch ('hockey stick') disagreeing.

"The disagreement between two climate scientists that will decide our future"
theconversation.com/the-disagreeme…

What's a mere interested planetary citizen to think? First of all, you ought to notice that this could matter, a lot, is potentially very serious, so we ought at least to take a precautionary approach. But we aren't, and won't.

FWIW, I observe that on the satellite data, absorbed solar radiation is increasing, and that increase appears to be accelerating (the trend line is not straight). There are issues with this dataset (it's a hard thing to measure well), but is it *that far out*? Doubt it.

But there is that other measure, ocean heat content, measured by an army of robotic diving buoys. Does it show recent acceleration? Until not very long ago the answer was substantially no, more a regular, ~linear, increase (Mann's point). Except now:

The timing *does not match*, but there is clearly stuff happening. My view is that Mann is probably wrong.

There's perhaps more to learn – by looking at patterns of change instead of global averages. As @LeonSimons8 keeps pointing out, most of the fossil fuel aerosol pollution occurs in a narrowish band of the Northern Hemisphere latitudes.

@LeonSimons8 And most of the reduction in fine particulate pollution is *there*. (And mostly it seems to be over the oceans there, a separate argument.)