Tag Archives: Greenland

Hansen worries that all hell will break loose

Hansen-paper-370x232_250James Hansen worries that “we may be approaching a point of no return, a situation in which our children inherit a climate system undergoing changes that are out of their control, changes that will cause them irreparable harm”. He’s looked at the models, at current observations, and at what happened during the Eemian interglacial 118,000 years ago, and he doesn’t like what he sees.

During the Eemian, when global average temperatures were about 1°C more than now, sea level was about 3-4 metres higher than now for a considerable time. Then about 118,000 years ago, towards the end of the interglacial, it peaked at 6-9 meters, including a rise of 2-3 metres within several decades. A similar sea level rise of several metres now would see the inundation of many of the world’s major cities.

Also there were huge storms at mid-latitudes in the North Atlantic which would make Superstorm Sandy look mild. Hansen thinks that climate change may be entering a phase where similar events could occur this century. Continue reading Hansen worries that all hell will break loose

Climate clippings 160

1. Game changing steel to make lighter cars etc.

From Gizmag, courtesy of John D:

    Back in 2011, we wrote about a fascinating new way to heat-treat regular, cheap steel to endow it with an almost miraculous blend of characteristics. Radically cheaper, quicker and less energy-intensive to produce, Flash Bainite is stronger than titanium by weight, and ductile enough to be pressed into shape while cold without thinning or cracking. It’s now being tested by three of the world’s five largest car manufacturers, Continue reading Climate clippings 160

Climate clippings 152

1. Speed of Glacier Retreat ‘Historically Unprecedented’

Glaciers observed in a recent study are losing between half a meter and one meter of ice thickness every year – two to three times more than the corresponding average of the 20th century. Continue reading Climate clippings 152

Climate clippings 151

1. Shorten gets solar + storage and the energy revolution

It’s happening, he says, through the action of consumers and industry.

    “This is a consumer revolution, as much as it is an energy transformation empowering Australian households, communities and businesses,” Shorten said. (It is) putting control back in the hands of the user, shifting the balance away from big power companies.”

Continue reading Climate clippings 151

Climate clippings 147

1. New beaut solar technology from UNSW

PERC technology developed by UNSW is likely to become standard in more than half of all solar cell production across the globe by 2020, ushering in new dramatic falls in the cost of solar technology. Continue reading Climate clippings 147

Climate clippings 130

1. Manicured lawns produce more greenhouse gases than they soak up

Grass_cropped_550

Researchers found:

that a hectare of lawn in Nashville, Tennessee, produced greenhouse gases equivalent to 697 to 2,443kg of carbon dioxide a year. The higher figure is equivalent to a flight more than halfway around the world.

If you use a mulching mower, don’t fertilise, limit cutting and watering, you might tip the balance in favour of the planet. But then your lawn might not be as lush.

2. Risk of extreme climate outcomes

Across the ditch Hot Topic takes a look at a new book by economists Gernot Wagner and Martin Weitzman called Climate Shock: The Economic Consequences of a Hotter Planet. They start with the notion that climate stabilisation forecasts regularly show that there is a 10% chance of warming reaching 6°C or more. Although not talked about much, this is standard fare and can be read off this graph I have posted multiple times:

Stabilisation probabilities_cropped_600

The 10% chance of reaching 6°C comes with greenhouse gases (CO2e) at around 580 ppm. We are currently at 480 ppm.

The whole insurance industry is predicated on probabilities of considerably less than 10%. The authors are suggesting that low probability extreme events should be taken seriously by governments. A 10% chance of climate Armageddon is not particularly low.

Weitzman was on the case back in 2008, when I did a post on him at LP, unfortunately in a gap in the archive. Peter Wood did a submission to the Garnaut Report on the subject. Garnaut, it must be said, looked the other way.

3. Arctic sea ice excitement

There has been some excitement over Arctic sea ice extent. As of now, unless there is a peak in late March, which is possible, the winter maximum is looking like a record low. This picture simplifies the story:

Sea ice Mr 15_cropped_600

It shows 2012 and 2015 ice extent against the 1981-2010 average. In the short term ice can be compacted by storms, or flushed out through Fram Strait. A cold snap can extend the ice with a thin cover. Also, as we see in 2012, winter maximums tell you nothing about summer minimums.

That’s the short story. You can read more here, here, here and here.

4. Greenland melting speeds up

As scientists upgrade their models of ice sheet decay, Greenland has a habit of exceeding their expectations.

According to the Intergovernmental Panel on Climate Change, Greenland ice loss has increased a phenomenal 632 percent since 2001. (14) This increase is coming from melt, sublimation (ice evaporating directly without melting first), melt penetrating to the bottom of the ice sheet through crevasses and moulins, and from rapidly warming Arctic Ocean waters penetrating beneath floating outlet glaciers, destabilizing these glaciers and increasing their flow.

Massive gorges have been found beneath the ice where rapidly warming seawater has the chance to circulate deep beneath the ice sheet.

A large aquifer has been found under the ice above sea level.

Soot forms on the ice from as far away as Siberia. As the ice sublimates, that is evaporates directly into the air, the soot remains to further decrease reflectivity.

2015_0305greenland1_550

The knowns and the known unknowns add up to a pretty grim picture.

5. EU progress on renewables

Commendable progress is being made on renewable energy in Europe.

Renewables contribute 26% of EU electricity, 17% of heating and cooling and 5% of transport, … It’s generally thought to be easier to decarbonise the electricity sector than heating or transport, where oil and gas continue to dominate.

This chart refers to electricity:

EU_renewables-electricity-production-2013_599x393

Apart from hydro, wind (light blue) easily eclipses solar (yellow).

When heating and transport are included, renewables comprise 20% of all energy, and the composition changes dramatically:

EU_renewables-primary-production-2013_599x393

An old technology, renewable wood, easily dominates through selective forestry.

In recent times energy usage has fallen, with the EU now using as much energy as it did in 1990.

The UK is the biggest laggard in meeting individual country targets. Four countries, Sweden, Estonia, Lithuania and Bulgaria, are ahead of target.

Wind has the momentum in the US with forecasts that it could supply 35% of electricity by 2050, or even as much as 41%. Within 10 years wind could be cheaper than existing coal.

6. 90% of Australian coal plants ‘at risk’ of being stranded assets

Oxford University’s Smith School of Enterprise and the Environment has compiled a Stranded Assets Programme report.

It is food for thought for Australia, then, that the Oxford report has declared it owner of “by far” the most carbon-intensive sub-critical fleet in the world (followed by India and Indonesia), with a whopping 90 per cent of its total 29GW of coal-fired generation capacity coming from 23 subcritical plants.

From The Guardian:

Coal currently provides 40% of the world’s electricity and three-quarters of this is produced by the most-polluting, least-efficient and oldest “sub-critical” coal-fired power stations. The International Energy Agency calculates that one in four of these sub-critical plants must close within five years, if the world’s governments are to keep their pledge to limit global warming to 2C.

Help is at hand, according to a group of Queensland engineers.

The Callide Oxyfuel Project is one of just a few low-emission coal projects in the world, and demonstrates how carbon capture technology can be retrofitted to existing power stations.

The technique has been on trial at CS Energy’s Callide A coal-fired power station at Biloela, in a project worth $245 million.

They reckon they’ve done it on a 30-megawatt plant and now need to scale it up. Predictably, not everyone agrees it’s worthwhile.

7. CO2 emissions flat in 2014

Global energy-related CO2 emissions flatlined last year, according to the IEA.

Following an announcement earlier this week that China’s CO2 emissions fell 2 percent in 2014, the IEA is crediting 2014’s progress to China using more solar, wind and hydropower while burning less coal. Western Europe’s focus on sustainable growth, energy efficiency and renewables has shown that emissions from energy consumption can fall even as economies grow globally, according to the IEA.

Global CO2 emissions stalled or fell in the early 1980s, 1992 and 2009, each time correlating with a faltering global economy. In 2014, the economy grew 3 percent worldwide.

The story is about energy efficiency as well as growth of renewables. Cheaper fossil fuels could lead to a resumption of fossil fuel growth in 2015, however.

Climate clippings 105

1. Atlantic Ocean important for heat storage

Most of the energy from global warming goes into the ocean as this graphic from Skeptical Science illustrates:

GW_Components_570

The linked paper stresses the role of the Atlantic in heat uptake. The following graph shows the heat uptake for the four main oceans. The black line is the sea surface temperature, the red line shows the heat below 1500 metres.

oceanheatuptake_chentung-2014-_550x496.jpg

All this is considered in relation to the socalled warming ‘hiatus’. The suggestion is that the Atlantic Meridional Overturning Circulation is the critical influence and it changes phase every 20 to 35 years. If so the ‘hiatus’ could last another decade or so.

Other scientists see the hiatus as multi-causal. It also depends which temperature series you are looking at. The HadCRUT temperatures always look flatter in recent years, as in this article. The Gistemp series from NASA has 1998 as about the third highest and shows a continuing upward trend, albeit slowed..

2. ‘Unprecedented’ ice loss in Greenland and Antarctica

Since 2009 the volume of ice loss has tripled in West Antarctica and more than doubled in Greenland, the highest rate of ice loss since satellite records began 20 years ago.

While it’s still early days, sea level rise this century could surprise on the upside.

3. El Niño watch

Carbon Brief also have the latest on the chances of an El Niño developing in 2014, which the Australian BOM now put at about 50%. Earlier there was talk of a super El Niño, which is still possible.

4. China gets into emissions trading

The Chinese national market will start in 2016.

The Chinese market, when fully functional, would dwarf the European emissions trading system, which is now the world’s biggest.

It would be the main carbon trading hub in Asia and the Pacific, where Kazakhstan and New Zealand already operate similar markets. South Korea will start a national market on Jan. 1, 2015, while Indonesia, Thailand and Vietnam are drawing up plans for markets of their own.

Looks like quite a trend. Time perhaps for Australia to join in!

5. World’s poor need grid power, not just solar panels

Small scale solar power is quite popular in Africa and supported by environmentalists. A few panels are able to run a few lights, a radio, charge the mobile phone but stop short of boiling a kettle. Critics see this as condemning the poor to a constrained future. Only 20% of Kenyans are connected to the grid.

Coal fired power is obviously not the answer. Dams take years to build, are typically over budget, inundate fertile lands or forest areas and interrupt natural stream flow.

In the Democratic Republic of Congo the mega project of the Inga 3 dam is due to start construction on the Congo River. If fully developed it will produce twice as much electricity as the world’s largest, the three Gorges in China. But will it be economically justified and what impacts will it have on the environment?

6. Emissions from energy generation jump after carbon price axed

Carbon emissions from the country’s main electricity grid have risen since the end of the carbon tax by the largest amount in nearly eight years.

Data from the National Electricity Market, which covers about 80 per cent of Australia’s population, shows that emissions from the sector rose by about 1 million tonnes, or 0.8 per cent, at an annualised rate last month compared with June.

That is the biggest two-month increase since the end of 2006, and came as a result of an increase in overall demand and a rise in the share of coal-fired power in the market, according to Pitt & Sherry’s monthly Cedex emissions index.

From what I can make of it, gas is increasingly going to export, there is some scaling back of hydro, presumably because of the weather. and large scale solar was killed off ages ago. The slack is being taken up by old coal, including brown coal.

Abbott’s strategy of saving the coal fired power industry seems to be working.

Building new more efficient coal would be his ultimate aim. This would involve investors and lenders having confidence in the future of coal. Surely they can’t be that stupid!

Reminder: Use this thread as an open thread on climate change.

Climate clippings 102

This week we start with trouble at the top and bottom of the world and finish with trouble with our leading media magnate and politician.

1. Geenland at a tipping point?

THE cracks are beginning to show. Greenland’s ice sheets slid into the sea 400,000 years ago, when Earth was only a little warmer than it is today. That could mean we are set for a repeat performance.

If Greenland goes, West Antarctica also goes, giving 13 metres of sea level rise from those sources. If that happens there will also be a complete loss of other glaciers and ice caps, thermal expansion and some partial melting from East Antarctica. A mess!

The question is how soon and what can we do? The answer is we need more research and we need to think more in terms of centuries.

We should be thinking about the next 500-1000 years, how ice sheet decay can be minimised, stabilised and headed in the other direction. Our plans for the next 50-200 years should be made in the light of this.

This image from the article shows a part of Greenland where the ice is quite dynamic.These areas are expected to grow.

New scientist_mg22229752.600-1_300

Here’s an image from another article:

greenland_cs_500

2. Big trouble in the Antarctic has been brewing for a long time

David Spratt at Climate Code Red:

“A game changer” is how climate scientist Dr Malte Meinshausen describes newly published research that West Antarctic glaciers have passed a tipping point much earlier than expected and their disintegration is now “unstoppable” at just the current level of global warming. The research findings have shocked the scientific community. “This Is What a Holy Shit Moment for Global Warming Looks Like,” ran a headline in Mother Jones magazine.

Meinshausen says this is new information. He says that the beaches we know and love all around the world will disappear. He also wonders what other nasty surprises lie this side of a 2°C temperature rise. Spratt says we told you ages ago it was coming, by James Hansen, for example and by himself and Philip Sutton in 2007.

This NASA image shows the temperature changes from 1957 to 2006:

AntarcticaTemps_1957-2006_lrg_600

Hansen warned; Meinshausen says it’s happening. Spratt warns:

It’s par for the course for climate policy-makers to hope for the best, rather than plan for the worst. More than once this blog has warned that sea-level rises are being underestimated by Australian policy-makers, and that the tens of millions of dollars being put into adaptation planning for sea-level rises of no more than 1.1 metres by 2100 will be a waste of money, and all that work will have to be done again. And now that has come to pass.

3. Huge ‘whirlpools’ in the ocean are driving the weather

GIANT “whirlpools” in the ocean carry far more water than expected and have a big impact on the weather – though as yet we don’t know exactly what.

The areas of swirling water are 100 to 500 kilometres across. These “eddies” generally move west, driven by Earth’s rotation, until they stop spinning. Now, for the first time, the amount of water and heat they carry has been measured.

Article and image available also here.

dn25801_1_300

4. Gorgeous BioCasa_82

Nestled into the pastoral landscape of Treviso, Italy, BioCasa_82 is a beautiful home that boasts some seriously energy-efficient technologies.

BioCasa_82_cropped_600

The house is made from 99% recyclable materials and scores

117 points out of 136, according to the American protocol LEED Platinum, and 10 out of 11 points in regards to innovation in design, the building is a real gem in the European building practice.

According to the carbon footprint analysis, BioCasa_82 yields 60% less emissions than traditional buildings. Its photovoltaic system produces around 14kWh/mq of electricity, and a high-efficiency geothermal plant provides heat, hot water and cooling. These strategies are complemented by a rainwater harvesting system.

5. Rupert Murdoch doesn’t understand climate change basics

That is everyone’s problem since he owns a world-wide media empire.

Many of Murdoch’s news outlets are also among the worst when it comes to getting climate science wrong and disseminating climate myths and misinformation. Inaccurate media coverage is in turn the primary reason why the public is so misinformed about global warming.

I won’t go into the details, but Climate Progress observes that he ‘lowballed’ the numbers and minimized possible impacts. Here in Oz:

”We can be the low-cost energy country in the world,” he said. “We shouldn’t be building windmills and all that rubbish.”

Elsewhere Graham Readfearn finds that Tony Abbott’s views on climate are seriously crap.

Reminder: Use this thread as an open thread on climate change.

Climate clippings 100

Kiribati_Fanning Is_478950-3x2-340x227Climate clippings_1751. Climate clippings reaches 100

Generally speaking I don’t rate the number 100 much except that it’s the number after 99 and the number before 101. Which might be just as well because when I was going through all the posts after transporting them (thanks tigtog) from Larvatus Prodeo I found two with the same number. So the 100th edition was actually number 99!

If you like to laugh Graham Readfearn has assembled 11 climate change comedy video clips to celebrate his 50th post on Planet Oz. I can recommend John Oliver and Australians for Coal, for example. There’s a bad language warning on the latter.

Huffpost has 9 Political Cartoons That Put Climate Change In Perspective:

slide_352590_3821132_free_500_cropped

2. Dust increases Greenland’s ice melt

A ‘normal’ Greenland summer melt is illustrated by the left-hand panel taken at 8 July 2012, when about 40% of the ice sheet was subject to melting.

Figure 8

The right-hand panel shows what happened for about a week thereafter and is not relevant except as a harbinger of things to come.

A new study looks at the increased melting from dust and soot. It found that a relatively minor decrease in the brightness of the ice sheet could cause double the average yearly rate of ice loss seen over the period 1992-2010.

assets-climatecentral-org-images-uploads-news-6_8_14_Brian_GreenlandDirtyIce-350x467

Soot resulting mainly from wildfires in North America and Russia has a greater melting impact than dust as such. However, increased dust is being produced in the Arctic and finding its way to the Greenland ice. Now 150 times as much dust as soot has been found at a site in the north-east.

While this can’t be extrapolated to the rest of the ice sheet, there is concern that Greenland melting could be greater than previously thought. See also Antarctic images for context.

3. Green jobs declining in Australia

Yes green jobs are declining in Australia:

Australia is one of the few places in the world where green jobs are decreasing according to figures released by the International Renewable Energy Agency.

Globally the sector now provides an estimated 6.6 million jobs, an increase of 800,000 from 2013 figures, but in Australia, jobs across solar photovoltaics and solar heating have declined, with up to 22 per cent of jobs lost in PV and 20 per cent in heating, according to Ethical Jobs general manager Michael Cebon.

This is happening:

entirely the result of government policy, both through loss of incentives at the federal level and backpedalling by state governments.

While a structural shift is occurring in the workforce elsewhere, Australia is regressing. The graphic shows the jobs potential of investment in various sectors:

comparison-fossil-and-renewable-380x513

4. Climate change impacts will ‘cost world far more than estimated’

That’s according to Lord Stern. He says that:

the economic models that have been used to calculate the fiscal fallout from climate change are woefully inadequate and severely underestimate the scale of the threat.

That includes those cited by the IPCC. They ignore the science, the full range of risks and simply assume away some of the worst economic impacts.

5. Historians will look back and ask ‘why didn’t they act?’

That’s the question asked by science historian Naomi Oreskes in her

latest book, The Collapse of Western Civilization: A View from the Future, [which] imagines a Chinese scholar in 2393 analysing the slow-motion disintegration of 21st-century democracies as they fail to tackle a growing environmental catastrophe.

It’s not a pretty picture.

By the end of the book, co-written with fellow historian Eric Conway, the Netherlands and Bangladesh are submerged, Australia and Africa are depopulated, and billions have perished in fires, floods, wars and pandemics. “A second dark age had fallen on Western civilisation,” Oreskes writes, “in which denial and self-deception, rooted in an ideological fixation on ‘free’ markets, disabled the world’s powerful nations in the face of tragedy.”

Oreskes and Conway say it’s a worst-case scenario, not a prediction.

One way or another, the game is up, we need to act with vigour and determination.

6. Coal to fuel human progress for decades – Tony Abbott

Our fearless leader has been strutting his stuff on the world stage, ignoring the science and embarrassing us all. He told Texan business leaders that:

we don’t believe in ostracising any particular fuel and we don’t believe in harming economic growth.

“For many decades at least, coal will continue to fuel human progress as an affordable energy source for wealthy and developing countries alike.”

Under the fig leaf of Direct Action anything goes.

Meanwhile Julie Bishop confirms that climate change won’t be high on the G20 agenda.

Once again they are out of tune with the nation. In a recent opinion poll 57% of those polled said the government should take climate change more seriously.

while more than half of respondents felt the federal government was the primary body which should address climate change, there was a negative rating of -18 when people were asked to rank the government’s performance.

This compares to a -1 rating from last year. These rankings are the differential between respondents’ “good” versus’ “poor” response to the government’s performance.

Reminder: Use this thread as an open thread on climate change.

7. Pacific presidents speak out against Australia’s stand on climate change

Out in the Pacific they are not happy with Abbott’s policy stance. The sea is coming up and they are going down. Here’s Fanning Island in Kiribati:

Kiribati_Fanning Is_478950-3x2-340x227

Climate clippings 98

This edition includes important updates on Greenland and Antarctica, global food supply, CSIRO cuts, CO2 levels moving decisively past 400 ppm and CO2 compared to global temperature rise.

1. Greenland may melt faster than expected

You may recall from the post Arctic images I included an image of the underlying topography of Greenland (Figure 5). It is saucer-like with large areas inland below sea level. The glaciers tend to drain through narrow gateways in the external rim. So they tend to be narrow and fast-flowing:

Glacier_assets-climatecentral-org-images-uploads-news-5_16_14_Andrea_Greenlandglacier-500x331

The mouths of most glaciers are melting from contact with warmer seas. It was felt that as this process continued the ice would lose contact with the water, slowing the melting.

New studies of the topography have shown that many of these channels are below sea level.

Valleys underlying many of the glaciers stay below sea level and extend much farther inland than previously suggested, so warm ocean currents that have migrated northward with the changing climate could eat away at the ice for much longer than current climate models suggest. “It will take much longer for these glaciers to lose contact with the ocean,” study author Mathieu Morlighem, of the University of California, Irvine, told Climate Central.

2. Melting Antarctica could devastate global food supply

A new report is the “first to factor in the effects of the slow-motion collapse of the Western Antarctica ice sheet on future food security.”

About time, I’d say.

The report acknowledges recent findings that that the retreat of the Western Antarctica ice sheet was unstoppable – and could lead to sea-level rise of up to 4 metres over the coming centuries.

“That sea-level rise would take out half of Bangladesh and mostly wipe out productive rice regions in Vietnam,” Nelson told The Guardian. “It would have a major effect on Egyptian agricultural areas.”

“A sea level rise of 3 meters (10 feet) over the next 100 years is much more likely than the IPCC thought possible,” the report said.

In terms of absolute land loss, China would be at risk of losing more than 3 million hectares (7.4 million acres). Vietnam, India, Bangladesh, and Myanmar could lose more than 1 million hectares (2.5 million acres), the report said.

The report recommends a radical increase in expenditure on agricultural research, which has been in decline everywhere over recent decades.

3. CSIRO cuts

The federal government cut CSIRO’s funding by $111 million over four years, which will result in 500 job cuts.

Dr Borgas [president of the CSIRO Staff Association] said a plan to move the Aspendale Laboratories to the organisation’s larger site in Clayton had been previously discussed but had come to nothing.

He said it was unclear whether the relocation would reduce the research performed by the 130 staff, which includes ice core analysis, air quality and pollution research and climate and atmospheric modelling.

Most countries planning for a future increase their scientific research funding.

4. CO2 levels decisively pass 400 ppm

During April all 12 World Meteorological Organisation northern hemisphere monitoring stations passed the 400 ppm mark, the first time ever. This is how such a level compares to the 800,000 year ice core record:

assets-climatecentral-org-images-uploads-news-5_2_13_news_andrew_co2800000yrs-500x282

When was it last this high? Possibly 15 million years ago, when it was warmer and there wasn’t much ice around.

“This was a time when global temperatures were substantially warmer than today, and there was very little ice around anywhere on the planet. And so sea level was considerably higher — around 100 feet [30 metres] higher — than it is today,” said Pennsylvania State University climate scientist Michael Mann, in an email conversation. “It is for this reason that some climate scientists, like James Hansen, have argued that even current-day CO2 levels are too high. There is the possibility that we’ve already breached the threshold of truly dangerous human influence on our climate and planet.”

5. Global temperature and CO2

I came across this graph from the NOAA National Climatic Data Center plotting CO2 levels against temperature rise. While correlation does not mean causation there is simply no alternative explanation.

assets-climatecentral-org-images-uploads-gallery-TVM-Global_Temp_and_CO2_web-600

If you take out 1998, which can be regarded as an outlier, the socalled ‘pause’ is only apparent from 2005, which is too short a time to mean anything.

There is another view which sees temperature responding in step-wise fashion. On that basis we may be due for another step, and with an El Niño likely…

Here’s one showing the ten warmest years on record, all since 1998:

assets-climatecentral-org-images-uploads-gallery-climate-matters-GlobalRecapRanking_sm-400x225

Reminder: Use this thread as an open thread on climate change.

Antarctic images

In this post I’ve included a series of explanatory images of the Antarctic in order to assist understanding the peril we are in from changes there, and why the Antarctic is going to be central to the climate change story over the coming centuries. What happens to the grandchildren of those who are children now is the big concern. In large part these images relate to items 2-4 of Climate clippings 96.

The first shows the giant vortex of winds, the strongest for at least 1000 years, ripping around Antarctica in a tight circle:

Figure 1
Figure 1

These winds draw rain away from southern Australia, and isolate Antarctica to some extent in terms of atmospheric warming. But they also churn up the ocean, leading to deeper mixing of heat and greenhouse gases.

Both the deep and the shallow formations of the thermohaline circulation system wrap themselves around the Antarctic:

Figure 2
Figure 2

One way or another warm water is penetrating through to Antarctica. The underlying topography of Antarctica reveals much of the land lying below sea level:

Figure 3
Figure 3

The borderline between blue and green marks sea level. Warmer water is coming directly into contact with the ice sheet and chewing away at the bottom of the ice shelves which form plugs holding up vast quantities of ice in the glaciers stretching hundreds of kilometres inland. The following image shows how the continent drains:

Figure 4
Figure 4

There is concern now that West Antarctica has tipped and with East Antarctica also more vulnerable than previously thought, sea level rise of some metres is now inevitable even if we were to somehow instantly curb greenhouse emissions.

Greenland is quite a different problem. For starters the underlying topography is saucer shaped, with glaciers exiting to the sea through ‘gates’. This image shows the topography:

Figure 5
Figure 5

Greenland melts very much from the surface, so its largely a matter of meltwater penetrating, indeed plunging at times, through the surface to the rock below and glaciers speeding up. This image shows some people standing where I’d never stand:

Figure 6
Figure 6

This image shows melting covering the entire Greenland ice sheet for a few days in 2012:

Figure 7
Figure 7

The panel on the left shows a more typical summer melt pattern, which is advancing noticeably over short time frames of a few years.

In the Antarctic, this image shows surface warming over the period 1981-2007:

Figure 8
Figure 8

But with the average temperature around -39°C on the East Antarctic ice sheet, which is four kilometres high, that huge lump of ice is relatively stable. This image from NASA in 2005 shows significant perimeter surface melting around East Antarctica:

Figure 9
Figure 9

The new research sees concern that warmer sea waters may destabilise the ice further inland than previously thought. Match the red blobs on East Antarctica with the drainage map at Figure 4.

Of some some concern and some comfort is the Andrill Project which found that “the West Antarctic ice sheet has collapsed and regrown over 60 times in the past few million years”. This image shows what happened about a million years ago over a 12,000 year period:

Figure 10
Figure 10

Concern because the Andrill research shows what can happen with mild orbital forcing (the Milankovitch cycles) as the main driver. I understand that CO2 concentration back then was only 400 to 450 ppm, which is where we now, implying that we are already committed to wasting the West Antarctica ice sheet. There is some comfort, however, that a change in the orbital forcing, which is far weaker than what we are doing now, arrested the melt in West Antarctica and brought the ice sheet back again. There was no tipping point which saw the whole East Antarctic sheet disappear.

For perspective I’ll post one of my favourites, a graph from David Archer in 2006 showing the broad relationship between temperature and sea level:

Figure 11
Figure 11

Do not connect the dots with straight lines. Most importantly, I think we now stand at the upper level of a 2°C interval where the sea level did not change much. The NH continental ice sheets had disappeared and the remaining ones – Antarctica, Greenland and the Arctic – were not seriously in play. Even now the main sources of sea level rise lie elsewhere. This table (13.1 from the IPCC5 WG1 Technical Summary) shows what’s happening:

Figure 12
Figure 12

That’s hard to read, so here are the figures for the average annual expansion for 1993-2010:

    Thermal expansion – 1.1mm

    Glaciers except Greenland and Antarctica – 0.76mm

    Glaciers in Greenland – 0.10mm

    Greenland ice sheet – 0.33mm

    Antarctic ice sheet – 0.27mm

With 4-5°C we can expect complete deglaciation and 75 to 80m sea level rise, made up of East Antarctica 59m, Greenland 6-7m, West Antarctica 5-6m, other glaciers and ice caps about 0.5m and thermal expansion, I don’t know, but I think in single figures. Greenland and Antarctica are accelerating rapidly and some time this century will become the top two contributors. These graphs from Skeptical Science are instructive:

Figure 13
Figure 13

Greenland and West Antarctica are in a death spiral of accelerating ice sheet decay. It’s happened 60 or more time before in recent paleo history. West Antarctica, being more vulnerable may overtake Greenland.

One could say from this that East Antarctica is not yet in play, but science seems to suggest it is not far away.

When ice sheet decay gets going Hansen sees it as possibly progressing in geometric fashion, producing a curve like this:

Figure 14
Figure 14

My thinking is that East Antarctica will tip sometime in the next decade, and that ice sheets will decay from there in a pattern that is more exponential than linear. Hansen’s scenario, which he puts forward as a serious possibility, does not look crazy.

I suspect that we are already committed to double digit sea level rise, and there’s not a thing we can do to prevent it; the question is when will it happen? We can only adapt and minimise.

I suspect also that things will go seriously pear-shaped during the latter part of this century. Pity our grandchildren’s grandchildren.

Update: There is a short ABC video news item about the Antarctic ice melt doubling since the last survey. At the end it says the process could take 1000 years. For a complete melt that would be lightning fast – 7.5 to 8 metres per century, or a metre every 12-13 years. We are pushing the system more than 10 times faster than it has ever been pushed before.

See also Gareth Renownden Goodbye coastline: we are beyond the point of no return.

Climate clippings 83

Climate clippings_175These posts are intended to share information and ideas about climate change and hence act as an open thread. Again I do not want to spend time in comments rehashing whether human activity causes climate change.

This edition contains items, exclusively, I think, in climate science and impacts. The thread is meant to function also as a roundtable to share information and ideas.

1. Climate change picked the crops we eat today

The New Scientist carries a story about how some cereals we know today were changed by the climate as we came out of the last ice age. Researchers at the University of Sheffield, UK took seeds of precursors of modern wheat and barley found with human remains in a 23,000-year-old archaeological site in Israel. They grew these together with four wild grass species that aren’t eaten today, but were also known to grow in the region at that time, and grew them under conditions replicating levels of CO2 then and also the higher levels when farming first arose 10,000 years ago.

All the plants grew larger under the higher levels of CO2, but the relatives of wheat and barley grew twice as large and produced double the seeds. This suggests the species are especially sensitive to high levels of CO2, making them the best choice for cultivation after the last ice age.

The team plan to look at whether other food staples around the world are similarly affected by elevated CO2 levels, for example millet grown in Asia and maize in North America. They also plan to compare the effects of CO2 on legumes such as peas. Continue reading Climate clippings 83