Irreversible Collapse Of Climate Alarmism
News media around the world have been all abuzz, with headlines declaring “Irreversible collapse of Antarctic glaciers has begun” and “West Antarctic Ice Sheet collapse is under way.” The “rapid” collapse threatens to cause sea level change of 4 to 13 feet. Calamity will surely follow. “Collapse will change the coastline of the whole world” shrieked the UK's Guardian, always a good source for mindless rumor mongering. What they are referring to are a pair of new reports that say the West Antarctic Ice Sheet (WAIS) has pushed its way over a submerged ridge that had been impeding its forward progress, causing the ice sheet to become unstuck from the sea floor. The WAIS is now flowing more freely, and hence more rapidly, into the sea. What the alarmist headlines don't say is that any impacts from this change are centuries to millennia in the future.
The two studies, one by NASA and the other by researchers at the University of Washington, looked at the Western Antarctica Ice Sheet over different stretches of time. The NASA study focused on melting over the last 20 years, while the University of Washington used computer model to predict the future of the WAIS. At least one of the papers could be considered real science, the type that takes actual measurements. Regardless, both studies arrived at similar conclusions: The thinning and melting of the Antarctic ice sheet is underway and cannot be halted. But that is not the whole story.
In fact, the screaming headlines obscure most of the facts of the situation—truth sacrificed in the name of sensationalism. What is not clearly stated is that all glaciers, including the WAIS and those on Greenland, are constantly flowing down hill. The reason they flow is that they are constantly gaining mass from accumulated snowfall. Glaciers grow from the top and the added mass causes the ice to flow down hill. If they are in a coastal area they can flow into the sea where chunks break off forming icebergs. If the ice was on land, its addition to the ocean will cause sea level to rise.
“Western Antarctic ice sheet collapse has already begun, scientists warn. Two separate studies confirm loss of ice sheet is inevitable, and will cause up to 4m of additional sea-level rise,” trumpeted the Guardian. “Collapse will change the coastline of the whole world!”
The often loony Huffington Post was a bit more measured in its reporting. “Part Of West Antarctic Ice Sheet Starting Slow, Unstoppable Collapse, Studies Indicate,” their headline stated. They too, said that the “alarmed” scientists expected even more sea level rise than previously predicted. Granted, the language used by the researchers was a bit alarming to those not familiar with the terminology used by glaciologists and other students of ice.
“The system is in sort of a chain reaction that is unstoppable,” said NASA glaciologist Eric Rignot, chief author of the NASA study in the journal Geophysical Research Letters. “Every process in this reaction is feeding the next one.”
“There's been a lot of speculation about the stability of marine ice sheets, and many scientists suspected that this kind of behavior is underway,” said Ian Joughin, a glaciologist at the University of Washington's Applied Physics Laboratory (APL) and the first author on the computer model paper. “This study provides a more quantitative idea of the rates at which the [ice sheet] collapse could take place.”
What they are most afraid of is that the grounding line, the boundary where a glacier touches the sea floor, could retreat, allowing warm water to undermine the ice and accelerate its melting. The NASA video below gives an idea of what the boffins are on about.
Bear in mind that rapid to scientists studying glaciers means something different from what rapid means to the average person. And while the word “collapse” implies a sudden change, the fastest scenario envisioned by the researchers is 200 years, and the longest is more than 1,000 years. Moreover, there are large uncertainties in these predictions because glaciers do not flow at consistent rates. Greenland's glaciers have recently demonstrated the variable nature of their march to the sea. The new “rapid” rate measures after the grounding line breakout in Antarctica will undoubtedly slow in the future. This leads to the question how fast is the ice shrinking in Antarctica? There are many different estimates.
What is in question here is the mass balance of the Antarctic ice, how fast is it shrinking or growing. Yes, I said growing. Glaciers are formed by accumulated snow and most are growing all the time. One online source gives the following growth rates. The Antarctic Peninsula has the highest accumulation rates (up to 1500 mm per year), followed by coastal West Antarctica, which has around 1000 mm accumulation per year. Compare this with the interior of the Antarctic Ice Sheet, where it is dry and cold; here accumulation can be less than 25 mm per year. For a detailed explanation of the aspects of ice accumulation see “Antarctic Ice Sheet mass balance,” on AntarcticGlaciers.org. That site summarizes the future trends this way:
Climate models predict that, for a generally warmer climate, snowfall will increase over Antarctica. Surface melt will increase around the more northerly Antarctic Peninsula, and dynamic changes such as increased ice discharge, ice-shelf collapse and grounding line recession, and marine ice-sheet instability are likely to offset any increases in precipitation. However, if no dynamical ice response is assumed, then increases in snowfall over the entire continent of 6-16% to 2100 AD and 8-25% to 2200 AD are likely to result in a drop in sea level of 20-43 mm in 2100 and 73-163 in 2200, compared with today. However, it is more likely that the Greenland and Antarctic ice sheets will lose mass over the next century, with rapid coastal changes, increases in ice flow and ice-shelf collapse all likely. As a result of these complex expected changes, there are a number of uncertainties in past, present and future ice sheet mass balance.
I added the emphasis on the last sentence of the quote above, mainly because many bloggers, tweeters and talking heads are giving the impression that this is a done deal—it is nothing of the sort. There could even be a decline in sea level in the future. Note that, with each new study, with each new measurement methodology, all the numbers tend to change. A 2012 study by NASA researcher Jay Zwally, “Mass Gains of the Antarctic Ice Sheet Exceed Losses,” claimed that input was exceeding output, but that was before the WAIS busted loose. Still, the report found the following:
- During 2003 to 2008, the mass gain of the Antarctic ice sheet from snow accumulation exceeded the mass loss from ice discharge by 49 Gt/yr (2.5% of input), as derived from ICESat laser measurements of elevation change.
- The net gain (86 Gt/yr) over the West Antarctic (WA) and East Antarctic ice sheets (WA and EA) is essentially unchanged from revised results for 1992 to 2001 from ERS radar altimetry.
Zwally goes on to say that “a slow increase in snowfall with climate warming, consistent with model predictions, may be offsetting increased dynamic losses.” Still, we don’t know how these rates of accumulation and melting compare to previous decades, so this is pure speculation on Zwally’s part.
So you see, as the Moody Blues once sang, it's a question of balance—growth vs loss. The figure below shows some past and recent estimates for total mass balance over Antarctica. A number of different measurement methods are shown. Each box is bounded by the time interval studied and the uncertainties identified.
Where does this leave us? Where science usually takes us, a state of uncertainty. The fact of the matter is that the ice drainage rate—ice melting or breaking off into the ocean—is highly variable, as is the accumulation of new ice from precipitation. The time scales for variation can be long, longer than a human lifetime, so any snapshot at a particular instant must be taken with a grain of salt (or crystal of ice). Despite the caterwauling in the media, this is yet another non-crisis crisis.
In fact, even while this new speedup in the WAIS's march to the sea has been found, Antarctica is setting new records for surrounding sea ice for a second straight year, baffling scientists seeking to understand why this ice is expanding rather than shrinking in a supposedly warming world. How soon we forget the plight of those high-minded eco activists who got themselves stuck in the summer ice around the southernmost continent.
If the media talking heads are to be believed, it is time to grab the dog and kids and head inland, for the seas are going to rise all around the globe. Even Jerry Brown, California's “Governor Moonbeam” has made a fool of himself over sea level rise drowning LAX, bemoaning the cost of relocating the airport. Remember, when glacier scientists use the words “collapse” and “irreversible” they don't really mean what the average person thinks they mean. Richard C. J. Somerville and Susan Joy Hassol are among those who have written papers on the communications gap between climate scientists and normal mortals.
There is a whiff of desperation in the air, and the over-hyping of these latest papers signals not the imminent decline of Antarctica’s glaciers but the irreversible collapse of climate alarmism. This latest climate change scare is a prime example of science speak sending the overly excitable media into an ignorance driven frenzy. It will pass. Another plane will disappear, another ferry capsize, more innocents will be abducted by cowardly terrorists somewhere, and the news ghouls will move on to the next disaster, real or imagined. Check on the Antarctic “collapse” ten years from now and you will find things much as they are today.
Be Safe, enjoy the interglacial and stay skeptical.