Tuesday, January 15, 2019

Guesses For the Update of the Doomsday Clock?

The Doomsday Clock, set every year by the Bulletin of the Atomic Scientists' Science and Security Board, will be reset this January 24th. It's currently set at 11:58:00 pm, up one full minute from 2016. (Here's their full list, which goes back to 1947 when it was 11:53:00 pm.)

Any guesses? There isn't much space left, but I'd be surprised if they can ignore Trump's heedless craziness for even a year, and the contribution of climate change to the hurricanes and wildfires in the US last year.

So I'm guessing they will set it forward by a half-minute.

You can watch this year's announcement on 1/24 on their Web site or Facebook page.

Are Underwater Volcanoes Causing Ocean Warming?

There's important climate news in the last week -- ocean warming has been found to be 40% higher than was given five years ago by the IPCC 5th Assessment Report, bringing it in line with climate model predictions. And Antarctic ice melt is six times greater than it was in the 1970s.

But I feel like blogging about the skeptical conjecture that underwater volcanoes are causing the observed ocean warming. For example, the radio host Lars Larson, whose show I was on last summer, conjectured that recently on Twitter:
Could this be causing ocean warming? Seems unlikely....

1) these volcanoes and vents didn't suddenly flare up during the Industrial era or in the 1970s -- they've been there for, what, billions of years at mid-ocean ridges where tectonic plate spread apart? 

2) But let's do a little back of the envelope calculation to estimate their influence -- for underwater volcanoes, at least. (Plus it's always fun to get a chance to make LaTeX equations again.) Here's what I found:

"About 5 cubic-miles of lava erupt every year along the mid-ocean ridges and submarine fault systems associated with subduction zones...." (Forbes)

The lava is at a certain temperature TL, and the ocean at (an average of) TO. As the lava pours into the ocean, it gives up heat to the ocean, raising the temperature by ΔT. The final temperature of the lava will be TO + ΔT. Then by energy conservation, the heat gained by the ocean is the heat lost by the lava:


where M is mass and C is specific heat. Then

so
where

Here are the numbers I found for lava:


where 1200°C was the maximum value in the given range. For the ocean:


(The initial temperature of the ocean doesn't matter much, since TL is over an order of magnitude larger.) So

α = 4.7 × 109 ≫ 1
and
ΔT = 3 × 10-7 K/yr

so tiny, as expected. Converting this to a ocean heat gain gives

ΔQ = 1 × 1018 J/yr = 4 × 1010 W → 1 × 10-4 W/m2

over the Earth's surface area. Compare that to the trend found in the first paper mentioned above of about 0.60 W/m2.

So undersea volcanoes only contribute ~0.1% of the ocean's heat gain.

(I think it's hard to imagine just how huge the ocean is. For example, it's 1.5 times more massive than Ceres, the largest body in the asteroid belt, with a diameter of almost 600 miles.)

Anything I missed?

Tuesday, January 08, 2019

Greta

Pacific Island Represent! (@PIrepresent)
We had the honour of meeting .⁦‪@GretaThunberg‬⁩, 15 year-old Swedish climate activist, at the global climate talks in Poland - #COP24. Change is coming ✊ pic.twitter.com/ppZtxX7jlg


Saturday, January 05, 2019

A Professional Scientist Actually Cited This Graph


Who? Roy Spencer. I'm not sure where it comes from, but it doesn't matter -- he needs to retake an undergraduate course in the proper presentation of data, because this graph is scientific malpractice. The proper response can only be this.

Of course, a proper graph -- recall from 5th grade that the point of a graph is to convey as much information as possible -- looks something like this:


and it would have error bars which I'm not going to bother with here. But you get the point. (Note 1/7: I replaced the original graph with one that includes the 1-year (4-quarter) moving average.)

And the 0.04°C on Roy's graph? (I get 0.05°C, but it makes little difference here except that it's just a little tiny additional 25%.) A real scientist would understand (as I'm sure Roy does; he's just more interested in propaganda) that: 

(a) it's really about heat gained, not temperature change, which for these data I find to be 1.4 x 1023 J. All that heat will not necessarily stay in the ocean, but much will come out to the atmosphere over millennia. The ocean is vast, and has a higher specific heat than air; if this amount of heat were in the atmosphere instead, the temperature change would be ~1000 times larger.

(b) for living things, the problem with ocean warming is that many of them live near the surface, for which the temperature change is much larger. (I wanted to plot the 0-100 m change in the ocean, but NOAA's site is down now because of Trump's moronic government shutdown.) So I have to go with this:


Comparatively, the temperature change of the top 700 m of the ocean is, over the same time period, 0.08°C, and the temperature change of the global sea surface is (HadSST3) 0.26°C. 

Ironically, Roy's post is about Chuck Todd's decision not to allow "climate deniers" on his television show, and how Roy claims there really aren't any climate scientists who deny that the climate isn't warming and man isn't partly responsible. (Except Fred Singer.) So Roy isn't a full-blown climate denier, but then he use the standard dumb denier trick graph that's the most climate denying graph of all. 

One more point. Roy ignores the entire professional literature and cites just one paper by Lewis and Curry, as if it's the final word. And he cheats on that, too, citing the CO2 climate sensitivity they found to be 1.0°C, when that's only the lowest value of their range (added 1/6: and anyway it's the range for the transient climate response -- the warming at the moment CO2 doubles, not ECS), which is 1.0-1.9 C (5%-95% confidence limits). 
Spencer: "...the lastest (sic) analyses (Lewis & Curry, 2018) of what this would mean leads to an eventual warming of only 1 deg. C from a doubling of atmospheric CO2 (we are currently about halfway to that doubling)...."
Now how can Roy think CO2's climate sensitivity is as low as 1.0 C, when 

(a) we've already had 1.0°C of warming.
(b) polluting aerosols are holding warming down by about 0.5°C, and
(c) CO2's share of manmade radiative forcing is, for 1990-2017, 66%.  

These would imply CO2's warming so far is (assuming CO2's radiative forcing fraction is the same since the pre-industrial era) 0.66*1.5°C = 1.0°C, when CO2 hasn't even increased by 50% yet, let alone doubled. 

And Roy is upset that Chuck Todd doesn't want to have the likes of Roy Spencer on his show, and in writing about it shows exactly why Todd doesn't.