Sunday, July 31, 2016

Ocean Heat Content Declines Significantly With the Large El Nino

Ocean heat content numbers are out for the 2nd quarter of 2016, and they show big drops from a year ago, due to all the heat released in the recent large El Nino.

The 0-700 meter OHC change was down 1.68 W/m2 from a year ago, and the 0-2000 m OHC change was down 1.51 W/m2.

The acceleration for the 0-2000 m region -- the top half of the global ocean -- is now [WARNING: numerology] down to 0.01 ± 0.03 W/m2, which is OK since about 10-20 years of data is necessary to reliably detect an acceleration, according to Wouters et al 2013.

Here's the history of 12-month changes in the 0-700 m OHC (the 0-2000 m OHC was reliably measured only beginning in 1Q2005):

I didn't mention this because it was widely reported elsewhere, but Cheng et al (including Kevin Trenberth and John Abraham) recently published a value for all-ocean all-depth OHC changes of 0.46 W/m2 from 1971-2005 and 0.77 W/m2 from 1992-2005.

No, this doesn't mean the end of global warming.

As ATTP writes, these numbers are in good agreement with the ensemble median of climate models:

especially when you consider the error bars, which I did not include above.

Climate models certainly don't predict everything accurately -- predictions are impossible anyway, except in hindsight -- but getting the energy imbalance right is probably the most important result of all.

Thursday, July 28, 2016

Summer Field, New Hampshire

Via Ann L'Italien.

Roy Spencer Makes It Easy to Dismiss Him

Roy Spencer wrote a brochure on climate change for the Texas Public Policy Foundation.

I'm sorry, but in my opinion the graph on the right-hand side of this figure is beneath the dignity of any academic or scientist:

If you're writing a report like this, why make it so easy to dismiss you?

PS: More pertinent questions. Don't expect an answer.

Monday, July 25, 2016

Global Sea Ice Extent Sets a Record Low Early Maxima

Global sea ice extent -- the sum of Arctic SIE and Antarctic SIE -- has two maxima in a year: one, the smaller of the two, usually in July, and the second, larger maximum, usually in November.

I don't think there's anything deep about this; it's just the way the nonsymmetric timing for the two poles works out, and the Arctic thawing more than the Antarctic.

This year, the first, lower maxima is a record low:

The trend in this local maxima is -40,400 km2/yr. This year is low mostly because Antarctic sea ice extent is low -- it's current anomaly (7/24/16) relative to a 1981-2010 baseline is just slightly negative, but that's a big change from recent years. Indeed, the trend for Antarctic SIE from the beginning of its record in 1978 is +21,700 km2/yr, while the Arctic has an overall trend of -53,800 km2/yr.

The overall trend in global SIE is -24,300 km2/yr.

There has been a recent paper on Antarctic SIE, by Meehl et al, that puts the increase due to the negative phase of the Interdecadal Pacific Oscillation, which is like the Pacific Decadal Oscillation (but I've never been able to find the data page for the IPO; if you know it, please let me know).

Tuesday, July 19, 2016

Jupiter As Seen From the Bottom

Wow. Just wow.

Image via NASA.

First Half-of-Year Records in Temperature and Arctic Sea Ice Extent


On a NASA teleconference, Gavin Schmidt, Director of GISS, said this record is "Not solely due to El Nino event." GISS calculates about 40% of record is due to El Nino and 60% due to other factors, including very, very strong Arctic warming."

Other things he said:

"The trend is very clear, and it's due to greenhouse gases."

"2017 is not going to be as warm as 2016." [due to starting the year in a neutral or La Nina condition]

"If 2016 sets a record, it will be the third record year in a row, which is unprecedented in our record." (99% chance 2016 sets a record.)

"May have some cooling in coming years, but the trends are going to continue, obviously."

"Paris thresholds are long-term equilibrium temperatures changes.....We are dancing with those lower [Paris] targets."

"No statistically robust that there is a strong acceleration" of warming. [Natural noise too hard to disaggregate. Natural trends pretty stable....] "It's premature to talk about acceleration in the 21st century."

For Arctic sea ice:

Friday, July 15, 2016

"Hope is the thing that is left to us, in a bad time."

North Brooklin, Maine

30 March 1973

Dear Mr. Nadeau:

As long as there is one upright man, as long as there is one compassionate woman, the contagion may spread and the scene is not desolate. Hope is the thing that is left to us, in a bad time. I shall get up Sunday morning and wind the clock, as a contribution to order and steadfastness.

Sailors have an expression about the weather: they say, the weather is a great bluffer. I guess the same is true of our human society—things can look dark, then a break shows in the clouds, and all is changed, sometimes rather suddenly. It is quite obvious that the human race has made a queer mess of life on this planet. But as a people we probably harbor seeds of goodness that have lain for a long time waiting to sprout when the conditions are right. Man's curiosity, his relentlessness, his inventiveness, his ingenuity have led him into deep trouble. We can only hope that these same traits will enable him to claw his way out.

Hang on to your hat. Hang on to your hope. And wind the clock, for tomorrow is another day.


(Signed, 'E. B. White')
From Letters of Note, via a comment at Slate

Thursday, July 14, 2016

La Niña Forecast: a Little Less Likely Than Last Month's

The IRI -- International Research Institute for Climate and Society -- at Columbia University just issued their ENSO forecast. It shows a little less likelihood of a La Niña forming this fall -- "about a 55-60% chance of La Niña during the fall and winter 2016" -- compared to last month's forecast of about 70%..

For comparison, here's last month's forecast:

Why does this matter? Only because...some people...are going to interpret a natural cooling fluctuation -- a La Niña -- as indication that manmade global warming is over, or was wrong, or a hoax, or a conspiratorial meme beamed into people's heads via picowaves.

Of course, the last year and a half has been a natural warming fluctuation, too. Mostly. This El Niño saw significantly higher surface and lower tropospheric temperatures, by about 0.3-0.4 C, than were seen in the large 1997-98 El Niño, which itself was about the same margin ahead of the big 1982-83 El Niño.

A better question is if the next La Niña is warmer than previous comparable La Niñas.

But naturally, if you accept AGW science, you feel somewhat confirmed by warmer upward fluctuations, and warmer downward fluctuations. It's sort of like this: imagine you saw Usain Bolt run as an 8-year old. That kid's fast, you think to yourself. Then you see him again when he's 12, and he's running even faster. He keeps making progress. Sure, he loses sometimes, but more often than not he wins, and when he does lose it's not by the margins he once did. This goes on for years and years -- he sets new records regularly, and when he doesn't, his time still brings up his average. And so it goes.

When you expect someone to run ever faster, it's interesting when he does and sets new records. More interesting than when he loses, even when it's by ever smaller margins. I mean, did you see him burst away from the field in Beijing?

PS: Yes, Usain Bolt is getting older and will someday be past his prime. It's not a perfect analogy -- climates don't get "old." Maybe the stock market is better, where ever higher records are expected over sufficiently long time periods.

Wednesday, July 13, 2016

Arctic Ice Extent Since 1850

From a new paper in Geographical Review by Walsh et al, and a press release from the University of Colorado. Note this is ice extent, which is more than just sea ice.

I'm looking to see if there's a time series plot....

Added: Here it is:

For comparison, the minimum sea ice extent in September 2012 was 3.62 Mkm2 (average for the entire month), so the ice extent was almost all sea ice at that minimum.

More About the McMillan et al result for Greenland Mass Balance

After this post last night about a new paper on Greenland ice loss over 2011-2014, I wrote to the lead author, Malcolm McMillan of  the University of Leeds in the UK.

He told me (as I suspected)
We don't look for an acceleration because the 4 year time period of our altimeter observations is too short to reliably detect this, given the large year-to-year changes in annual mass loss. So I wouldn't say that there is no acceleration, rather that, given its likely magnitude, it is not possible for us to reliably measure it over such a short time period.

For assessing accelerations in mass loss you really need to use the longer 10-20 year records which are better able to resolve this. You may be aware of it already, but in case you're not, the attached paper gives a nice analysis of the time periods required to detect certain accelerations.

I'm not aware of any reasons to expect the long-term acceleration to go towards 0.

Tuesday, July 12, 2016

Another Result on Greenland's Melt Rate

There's a new paper in GRL by Malcolm McMillan et al, "A high-resolution record of Greenland mass balance." They studied the period 2011-2014, mapping "recent Greenland Ice Sheet elevation change at high spatial (5 km) and temporal
(monthly) resolution." (They even modeled the firn, the granularity of the snow, because it influences the backscattered radar echo.) Their rate of ice loss, -269 Gt/yr, is close to other recent values, and (added 7/7) equivalent to a global mean sea level rise over this period of 0.74 ± 0.14 mm/yr, "approximately double the 1992–2011 mean." They find regions where glacier velocity has increased significantly in recent years -- "...only 0.9% of the total ice sheet area, have contributed more than 12% of the total mass balance during our study period."

But they don't seem to find any downward acceleration in these years:

They don't calculate an acceleration in their paper.... Has melt acceleration stopped, or is this just a blip upward? I would be surprised if it has stopped -- this latest paper only covered a 3-year period, while the others (below) were all over 10 years. That makes it a difficult to detect an acceleration -- just look at any 3-year interval on their graph -- the all look straight.

In any case, here is my collection:

Note 7/13: this is a change from the earlier table; the "--" means the four years in the McMillan et al study was too short an interval to reliably detect an acceleration. See here

Added 7/13: I give some remarks and clarifications by Malcolm McMillan here.

Gauging Greenland's Melt

An interesting video by Peter Sinclair for Yale Climate Connections.

These guys in the field always seem to be having a great time out there....

One of the scientists says it's looking like meltwater runoff is greater than dynamical ice discharge. That's also what was found in the 2014 Enderlin et al paper I wrote about here.

Monday, July 11, 2016

La Nina is Looking a Bit Shy This Year

The planet seems a little hesitant to jump into a La Nina, as measured by the sea surface temperature anomaly in the Nino 3.4 region.

Still, the last forecast for a La Nina this fall is over 70%, from Columbia's IRI. The forecasts come out monthly, usually around the middle of the month. Should be a new one soon.

Of course, should a La Nina happen the global mean surface temperature will drop, and that will mean manmade global warming is over and was never true in the first place and there's no greenhouse effect either because, like, the Second Law of Thermodynamics. Dummies.

Saturday, July 09, 2016

Response to the Weekly Standard Review of "Struggling for Air"

Here's another review of Struggling for Air by Revesz and Lienke, by Brian Potts in the Weekly Standard, a conservative publication. (I put some of my impressions of the book here.)

He emailed me to let me know about his article. You should read it too. I don't agree with what he wrote here:
But the first problem with Revesz and Lienke's conclusions in the book is that they completely ignore a critical component: cost.
As far as I know, there was nothing in the Clean Air Act that said cost was a factor; its charge, specified by Congress, was to identity and regulate emissions that had adverse effects "on public health and welfare."

But actually we do know the cost:

"How the Clean Air Act Has Saved $22 Trillion in Health-Care Costs,"
Alan H. Lockwood, The Atlantic 9/7/12.

So I get tired of hearing about cost, and especially about one-way interpretations of it, because the true cost is that coal causes health problems that are greater than the benefit it provides -- benefit as measured by the market price.

Coal's pollution kills people. It causes more heart attacks, more premature death, more asthma attacks. Conservatives, who should care deeply about the impact and cost such of negative externalities, instead not only ignore them, but whine about them.

It seems they think it is OK, and there is no cost, to rain pollution down on people's head.

I've cited these studies before, but this study, by the once-darling (to pseudoskeptics) environmental economist William Nordquist of Yale:
"Environmental Accounting for Pollution in the United States Economy," Nicholas Z. Muller, Robert Mendelsohn, and William Nordhaus, American Economic Review, 101(5): 1649–75 (2011).
found that generating electricity with coal or oil creates negative value -- that is, it sends the economy backwards. And kills people in the process.

This 2010 study by the National Academy of Sciences found that in 2005 there was at least $120 billion in damages done to the country, in 2007 dollars. 
(Why would anyone express damages in the year 2005 in anything but either dollars in the ydollars in the year the report was written, 2010? Talk about heads-in-the-clouds scientists.)

The cost of a fuel or power source is NOT what you see at the gas pump or on your monthly utility bill.

Don't the words "conservative" and "conservationist" come from the same root word? Yes, they do:

Which Side Are You On?

"Once again, the difference in policy views is clear, and can be coolly stated: those who insist on the right to concealed weapons, to the open carrying of firearms, to the availability of military weapons—to the essentially unlimited dissemination of guns—guarantee that the murders will continue. They have no plan to end them, except to return fire, with results we know. The people who don’t want the regulations that we know will help curb (not end) violent acts and help make them rare (not non-existent) have reconciled themselves to the mass murder of police officers, as well as of innocent men and women during traffic stops and of long, ghostly rows of harmless civilians and helpless children. The country is now clearly divided among those who want the killings and violence to stop and those who don’t. In the words of the old activist song, which side are you on?"

- Adam Gopnik, The New Yorker, July 8, 2016, "The Horrific, Predictable Result of a Widely Armed Citzenry"

Friday, July 08, 2016

Stuff I Recently Found Interesting

(I will probably add to this list today and tomorrow.)

From the Department of We-Will-Pay-For-Climate-Change-One-Way-Or-Another: Miami-Dade Could Ask Developers to Pay for Climate Change Costs. Georgetown University law professor J. Peter Byrne says:
"If that discourages the developers from building, that's OK. They can try to build it in a manner or location in which there's less climate harm," Byrne says. "We don't view it as really draconian or a severe regulation.... If I had to guess, I'd say this would become a fairly common tool in the future.""
By the way, the long-term linear trend in sea level at Key West is, I find, 2.4 mm/yr. (The global average is now 3.4 mm/yr.) But it's accelerating upward, and it's the nonzero acceleration that dominates projections. (12 months ago SLR was 3.3 mm/yr. But the El Nino is probably to a higher than average recent of rate of SLR, because the accelertion of the entire Aviso dataset is now 0.037 mm/yr2. That seems tiny, but the difference between the quadratic and linear projections to the year 2100 is 17 cm. (Forewarned: I might be doing nothing but numerology here; I'm certainly not doing physics.)

America is becoming Afghanistan: a brutal comment in the NY Times.

This says the recent flooding in West Virginia was a 1000-year event. They were the third deadliest floods in West Virginia. I don't know how to adjust that for improvement in infrastructure and the capabilities of emergency response.

Stupid: The US Senate just voted to require labeling of foods containing GMOs. The House is expected to pass it as well. 107 Nobel Laureautes just sent a letter giving Greenpeace grief for their unscientific anti-GMO stand.The left can be just as anti-science as the right (GMOs and fluoridation of drinking water immediately come to mind).

"Evolution May Have Moved at a Furious Pace on a Much Warmer Earth":
University of North Carolina researchers show that rates of spontaneous DNA mutation could have been 4,000 times higher than they are now, thanks to a hotter planet billions of years ago. (Newswise)

Also from Newswise: "Warming Pulses in Ancient Climate Record Link Volcanoes, Asteroid Impact and Dinosaur-Killing Mass Extinction"

Question: Why do the police have to ask for registration and insurance in this day and age? Why isn't the information immediately available via car-computer or a simple phone call after they stop someone and go back to their patrol vehicle?

I'm not exactly sure what this means, but on first glance it doesn't sound good: "...'around a third of all developed-country government debt—or more than $7 trillion, in terms of market value—is now trading at negative yields,' meaning that buyers are willing to pay more for these bonds than they will eventually get back if they hold them to maturity."

Wednesday, July 06, 2016

UAH Lower Troposphere vs. GISS, Detrended

Here are the detrended data for UAH LT v6beta6 and GISS, monthly:

The 1997-98 El Nino still stands out. So does a weird upward blip in UAH in January 2013. And, as Layzej conjectured, UAH LT does tend to have higher peaks than GISS during El Ninos (though not this year), and deeper drops during La Ninas.

Finally, since LT temperatures typically lag GISS by a few (?) months, I plotted the difference between UAH_LT_detrended_with_a_3-month_lag and GISS_detrended:

Comparing Surface and Satellite Temperatures for El Ninos

In the comments of this article, Layzej asked why the peak lower tropospheric temperatures of the El Nino that just ended were about the same as the peak in GISS surface temperatures, whereas they were about 0.15 C higher for both the 1997-98 El Nino and the 2009-10 El Nino. He pointed to this chart from WFT, which uses version 5.6 of UAH's LT dataset.

Perhaps WFT is waiting for UAH v6 to come out of beta, and if so I can't blame them. Frankly I think UAH should not even have introduced a beta version of version 6, except internally, but should have done like NOAA with the Karl et al Science paper of 2015, when the data were released in a set version and published when the paper itself was published. UAH says their paper is still in peer review.

Anyway, here is a comparison between UAH LT v6beta6 and GISS. I've adjusted the GISS anomalies to have the same baseline as UAH, 1981-2010, and smoothed the data with a 12-month moving average. The results look significantly different (any thoughts why?):

Tuesday, July 05, 2016

"Struggling for Air" is Worth Reading

Another excerpt from Struggling for Air by Richard L. Revesz and Jack Lienke, about a 1977 report of the National Academy of Sciences, when scientists were supposedly worried about the coming ice age. (There were questions about it, as smog was blocking sunlight before the era of clean air laws, but that's as far as it went.)

Struggling for Air is a good book, but it's kinda dry. It's subtitle is Power Plants and the "War on Coal," and its thesis is that administrations from Bush the 1st to Obama have all been trying to fix a flaw in the Clean Air Act of 1970 -- it regulated emissions for new power plants, but it allowed existing plants to be "grandfathered in." As long as an existing plant was only being repaired and maintained, it was exempt from the pollution standards of the Act.

Those who drafted the Clean Air Act believed, in part from industry testimony when the bill was being drafted by committee (led by Edward Muskie), that these existing plants had a lifetime of only 30-or-so years, and they would be retired in due course. The replacement plant would then have to meet federal standards.

By the way, there was strong support for the Clean Air Act of 1970 (which was actually a extension, but a significant extension, of the original Clean Air Act of 1963). It passed the Senate 73-0. And it was Nixon, a Republican, who signed it. And it was Nixon who created the Environmental Protection Agency, though probably not so much out concern for the environment -- he was much more interested in foreign affairs, and bogged down by the Vietnam War -- but to protect himself on the left from a possible 1972 presidential run by Edward Muskie (D-Maine), who was a strong environmentalist, and one of the first environmentalists in the Senate.

Anyway, coal companies, especially, used this loophole to their advantage, and to our respiration's disadvantage -- they kept the existing plants going far beyond their designed lifetimes -- up to 50 years or more, with patch upon patch. There was uncertainty from the EPA about whether a change in the plant was routine maintenance or an augment sufficient to make it a new plant, subject to regulation. How much of the plant can be changed before it's a new plant? It's like the old question about an ax: if you change the handle, and then later have to change the head, is it still the same ax?

By the way, there was no grandfathering in the Clean Water Act.

There was a constant struggle between industry, environmental groups and the EPA over this. Courts would decide one way, only for another court to vacate that ruling. Industry lobbyists and industry groups kept constant pressure on the EPA, through their legislators who, of course, they made very nice financial contributions to. 

Various presidents would push the EPA one way or the other. The EPA took several years to decide some things or implement changes requested by Congress, or even to write requested reports. 

Bottom line is there was much more pollution -- SO2, NOx and mercury -- emitted than anyone ever thought there would be. And that's true for CO2 also, because if corporations had been forced to update existing plants, it would have been with more efficient equipment and technology, and the plants wouldn't have burnt as much coal, so there would have been less CO2 produced along with fewer of the traditional pollutants. But no one knows how much less -- it's impossible to calculate. 

More people died prematurely because of this loophole, and fish and babies were exposed to higher quantities of mercury. There were more heart attacks and more asthma attacks. 

So the big three programs from the Obama administration -- the Transport Rule, the Mercury and Air Toxics Standards, and the Clean Power Plan -- weren't and aren't a "war on coal" -- they were all intended to close loopholes in the Clean Air Act and regulate pollution as Congress intended when it passed the Act in 1970, and amended in 1990.
The authors of this book also write that CO2 regulation fell under the Clean Air Act, since the EPA's charge was to identity and regulate emissions that had adverse effects "on public health and welfare." Maybe CO2's effects weren't clear in 1970, but they were by 1990, and in 2007 the Supreme Court, in Massachusetts v. EPA, ruled that CO2 met the definition of a pollutant under the Clean Air Act, meaning the EPA was finally obligated to regulate it. 

The authors of Struggling for Air are environmental lawyers, and they write like lawyers, with every detail included and properly cited. I found the first half of the book slow going, but when they got to CO2 in the last couple of chapters it was easy going, because I know more about that. But I learned a lot from this book, which has only 163 pages (not counting 52 pages of Notes containing the citations), and I'm glad I read it.

Center for American Progress is Passing Around Bad Data

Here's a chart of coal mining employment, in this Huffington Post article of two days ago:

(Update: The Huffington Post removed this plot (without saying so), but it appears in this document from the Center for American Progress.)

Notice the caption, and the orange part of the line that signifies Obama's presidency.

Except this chart is wrong. The orange part is all wrong.

The chart says the data are from FRED, the database from the Federal Reserve of St Louis. But here are the actual data from FRED:

Notice the difference after 2012.

In fact, about 33,000 coal mining jobs have been lost under Obama. No comment now on the merits of that, just that the Center for American Progress seems clearly to have altered the data to be pro-Obama.

ThinkProgress and ClimateProgress are under the umbrella of the Center for Amerian Progress. Recall, they're the ones who won't tell you who funds them. Their president used to be John Podesta, who was Deputy Chief of Staff for Bill Clinton and is now Chairman of the 2016 Hillary Clinton presidential campaign. Maybe publishing bad data is their way of helping her get elected.

You might want to start checking whatever data they present.

Update 4:00 pm - The Huffington Post removed the chart. (I had emailed the author.)

Monday, July 04, 2016

The Juno Spacecraft and Solar Cell Progress

Tomorrow/today, the Juno spacecraft will enter orbit around Jupiter. (03:18 UTC, 8:18 pm Pacific Daylight Time). This bodes well for Earth:
Another pretty cool thing is that the Juno spacecraft is powered by solar panels, which is something that until recently hadn’t been possible for outer planets. Sunlight is weaker out there, and it wasn’t until this mission that solar panels were efficient enough to power a spacecraft; on top of that the instruments are also very efficient with their power, allowing lower energy generation needs.
There are 18,698 solar cells, which generate 400 Watts at Jupiter's distance from the Sun (14,000 Watts at Earth's distance). Each orbit takes 14 days, and there 37 orbits are expected, so sometime next November or so it will plunge downward into Jupiter's mysterious interior.

It'd be interesting if it found an amusement park or something down there.

Lower Troposphere Sees Warmest 12 Months Ever

That's according to RSS. Their calculation of the temperature of the lower troposphere for June shows that its annualized temperature (12-month moving average) is at a record high:

UAH's calculations, which just moved to a new subversion, v6beta6, have the 12-month moving average at 0.02°C below the record high period of Jan-Dec 1998. But the endpoints of a "year" are arbitrary, right?

Sunday, July 03, 2016

New Paper on Sea Level Acceleration

There's a new paper in Geophysical Research Letters on sea level acceleration, by Phil Watson of Australia.

It finds acceleration.

Watson proposed what he calls "improved techniques" to measure real-time velocity and acceleration, and does so for five sets of global mean sea level (GMSL) data, each of which used a different technique. One is Church and White 2011, and you can see the rest below. Watson says existing estimates of sea level acceleration rely on a simple second-order polynomial fit to the entire dataset, then taking twice the coefficient of the quadratic term.

That's what I did here, and found a positive but small acceleration of sea level rise. Using the latest Aviso and CU data, which go through March, I find accelerations now of 0.036 and 0.028 mm/yr2, respectively.

Rahmstorf and Vermeer faulted the quadratic regression technique, "due to...focusing on records that are either too short or only regional in character, and on their specific focus on acceleration since the year 1930, which represents a unique minimum in the acceleration curve."

Watson tries to improve the temporal resolution of the data values. He does this by doing spectral analysis on the data, and finds signals "that have oscillations with a period of the order of ≈40 to 70 years." He thus isolates these slowly varying trends from the respective GMSL reconstructions, gets a much smoother dataset, and takes the first and second derivatives of a cubic fit. That's as far as I'm going into the weeds.

Here are his results (note: they're for maximum values, not the values at the end of the datasets.)

The data identifiers come from Church and White [2011], Jevrejeva et al. [2014], Hay et al. [2015], Ray and Douglas [2011], and Wenzel and Schröter [2014], with the last two numbers representing the end year of the data.

Ignoring the slightly different endpoints, that's an average maximum of 0.101 mm/yr2. J10 looks pretty out of whack.

And Watson finds a rate of sea level rise that is about what I find from a quadratic fit to the Aviso data, which at the end of 2014 was 3.18 mm/yr. Watson says "the application of these improved techniques suggests that current (≈2010 to 2014) rates of GMSL rise could be of the order of 3.08±0.31 to 3.52±0.03 mm/yr (95% ci) and rising with strong evidence of a recent acceleration commencing around 1982–1985."

Here are his results in graphical form, over time (thus, not maximum values).

As far as I see he didn't provide an acceleration up to 2014, as he did for velocity. Acceleration looks clearly affected by the 1998 El Nino, and probably is lately too.

Fun With Charon and Miranda

Phil Plait at Slate has an interesting article about the huge canyon on Charon, the large moon of Pluto. It's about 9 km deep and 700 km long.

The moon is small, meaning its gravitational forces are less likely to collapse large massive cliffs like this. The freefall time from that height is 4.2 minutes. Miranda, a moon of Uranus, has cliffs at least 10 km high. You could launch yourself off it and fall for 8.4 minutes. Of course, you'd need some way to stop from slamming into the cliff's base -- at the bottom of Charon's cliff you'd be traveling at 160 miles per hour, and 89 mph at Miranda's -- and of course parachutes don't work in a vacuum.

Anyway, this is all just an excuse to post this wonderful video by Erik Wernquist called “Wanderers.”

It shows people (I assume they're humans) jumping off the cliff of Miranda, and an inspiring view of a space elevator. (Space elevators are more feasible on smaller bodies; you could build a space elevator on our Moon out of a produced material called M5 (and almost Kevlar, but it has a tensile_strength/density ratio that's about 10% too low). There is no known material suitable for Earth; maybe carbon nanotubes, but just recently it was shown that that's not looking feasible. Someone will come with something, though, someday.)

Saturday, July 02, 2016

U.S. House warned of coal's potential demise in 1966

Interesting view from a 1966 report from the House of Representatives:


This appears in Struggling for Air: Power Plants and the "War on Coal," Richard L. Revesz & Jack Lienke, Oxford University Press, 1966 p. 119.