Showing posts with label albedo. Show all posts
Showing posts with label albedo. Show all posts

Sunday, January 16, 2011

2011 starts with lowest Arctic sea ice extent on record

The year 2010 was the warmest year on record, as confirmed by the WMO and as illustrated by the NOAA graph below.
This is the more dramatic given that we’re in the middle of a strong La NiƱa, which pushes temperatures down, while we’ve been in “the deepest solar minimum in nearly a century.” NOAA has meanwhile published the data for 2010. A chart based on NOAA data is added below, with standard polynomial trendline added.
As the NASA map below shows, temperature anomalies are especially prominent at higher latitudes, close to the Arctic. Arctic sea ice cover in December 2010 was the lowest on record for the month, said the WMO, adding that sea ice around the northern polar region shrank to an average monthly extent of 12 million square kilometres, 1.35 million square kilometres below the 1979 to 2000 December average. Furthermore, 2011 has started with the lowest Arctic sea ice extent on record for this time of the year, as shown on the International Arctic Research Center graph below.
On the NSIDC graph below, monthly September ice extent for 1979 to 2010 shows a decline of 11.5% per decade.
The NSIDC image below shows that, at the end of the summer 2010, under 15% of the ice remaining in the Arctic was more than two years old, compared to 50 to 60% during the 1980s. There is virtually none of the oldest (at least five years old) ice remaining in the Arctic (less than 60,000 square kilometers [23,000 square miles] compared to 2 million square kilometers [722,000 square miles] during the 1980s).
Why is all this so important? The Arctic sea ice acts as a giant mirror, reflecting sunlight back into space and thus keeping Earth relatively cool, as discussed in this open letter. If this sunlight instead gets absorbed at higher latitudes, then feedback effects will take place that result in much higher temperatures, in a process sometimes referred to as Arctic amplification of global warming.
Above image is from a recent study, which found that 2010 set a record for surface melting over the Greenland ice sheet. The study warns that surface melt and albedo are intimately linked: as melting increases, so does snow grain size, leading to a decrease in surface albedo which then fosters further melt. A recent study concludes that the rate of Arctic sea ice decline appears to be accelerating due to positive feedbacks between the ice, the Arctic Ocean and the atmosphere. As Arctic temperatures rise, summer ice cover declines, more solar heat is absorbed by the ocean and additional ice melts. Warmer water may delay freezing in the fall, leading to thinner ice cover in winter and spring, making the sea ice more vulnerable to melting during the next summer.
Thin lines are raw data, bold lines are three-point running means…. (C) Summer temperatures at 50-m water depth (red)…. Gray bars mark averages until 1835 CE and 1890 to 2007 CE. Blue line is the normalized Atlantic Water core temperature (AWCT) record … from the Arctic Ocean (1895 to 2002; 6-year averages)…. (D) Summer temperatures (purple) [calculated with a different method]
The IPCC didn't take such feedbacks into account and didn't foresee a total September sea ice loss in the Arctic for this century. Many scientists have repeatedly warned about this, as mentioned in this early 2009 post and this early 2010 post.
Projections that start with more recent data will take some of this feedback into account. Projections that start with 1992 and 1995 data, as in the pink and purple lines on above image, predict a total loss of September Arctic sea ice by 2040 or 2030. A study that used 2007/2008 data as starting point predicts a nearly sea ice free Arctic in September by the year 2037. Albedo change is only one of a number of feedback processes. A rapid rise of Arctic temperatures could lead to wildfires and the release of huge amounts of carbon dioxide and methane that are now stored in peat, permafrost and clathrates, which constitutes further feedback that could cause a runaway greenhouse effect. Heat produced by decomposition of organic matter is yet another feedback that leads to even deeper melting.
The cumulative impact of multiple feedback processes and their interaction reinforces and accelerates Arctic warming, making downward curved projections more applicable than straight line extrapolation of earlier data. The pink dotted line on above chart shows a scenario that reflects the impact of a number of feedback processes. A study at the University of Calgary concludes that, even if we completely stopped using fossil fuels and put no more CO2 in the atmosphere, we've already added enough carbon in the oceans to cause the West Antarctic ice sheet to eventually collapse (by the year 3000), resulting in a global sea level rise of at least four meters. In other words, we have already passed the tipping point for the West Antarctic ice sheet, and additional emissions could cause its collapse to occur much earlier. According to a study published in the journal Nature Geoscience, ice and snow in the Northern Hemisphere are now reflecting on average 3.3 watts of solar energy per square meter back to space, a reduction of 0.45 watts per square meter between 1979 and 2008. "The rate of energy being absorbed by the Earth through cryosphere decline – instead of being reflected back to the atmosphere – is almost 30% of the rate of extra energy absorption due to CO2 increase between pre-industrial values and today," co-author Karen Shell said. A study by by National Center for Atmospheric Research (NCAR) scientist Jeffrey Kiehl found that carbon dioxide may have at least twice the effect on global temperatures than currently projected by computer models of global climate. Melting of ice sheets, for example, leads to additional heating because exposed dark surfaces of land or water absorb more heat than ice sheets. Without changes, this new study warns, Earth's average temperature appears set to rise this century by 29°F (16°C), to levels never before experienced in human history. Such a rise would make that many areas on Earth would become too hot to live in. Humans and other mammals cannot survive prolonged exposure to temperatures exceeding 95°F (35°C), says Steven Sherwood. Heat stress would make many parts of the globe uninhabitable with global-mean warming of about 7°C (12.6°F). Warming of about 21°F (11-12°C) would make places where most people now live uninhabitable. I have made recommendations to deal with global warming for years, most recently in this Global Warming Action Plan. What do you think should be done?

Saturday, June 26, 2010

Open letter on Arctic Sea Ice Loss


Open letter on Arctic Sea Ice Loss


The Arctic sea ice acts as a giant mirror to reflect sunlight back into space and cool the Earth. The sea ice has been retreating far faster than the Intergovernmental Panel on Climate Change (IPCC) predicted only three years ago [1]. After the record retreat in September 2007, many scientists revised their predictions for the date of a seasonally ice free Arctic Ocean from beyond the end of century to beyond 2030. Only a few scientists predicted this event for the coming decade, and they were ridiculed.

In 2008 and 2009 there was only a slight recovery in end-summer sea ice extent, and it appears that the minimum 2010 extent will be close to a new record [2]. However the evidence from PIOMAS is that there has been a very sharp decline in ice volume [3], which is very worrying.

The Arctic warming is now accelerating, and we can expect permafrost to release large quantities of methane, from as early as 2011 onwards, which could lead inexorably to runaway greenhouse warming and abrupt climate change. All this could become apparent if the sea ice retreats further than ever before this summer. We could be approaching a point of no return unless emergency action is taken.

We suggest that the current situation should be treated as a warning for us all. The world community must rethink its attitude to fighting global warming only by cutting greenhouse gas emissions sharply. Even if emissions could be cut to zero, the existing CO2 in the atmosphere would continue to warm the planet for many decades.

Geoengineering now appears the only means to cool the Arctic quickly enough. A geoengineering project of the intensity of the Manhattan Project is urgently needed to guard against a global catastrophe. A multi-disciplinary team of scientists and engineers should be tasked and resourced to assess the evolving situation in the Arctic and implement a strategy of parallel research, development, preparation and deployment for different geoengineering techniques, such as to minimise the risk of failure.

Yours sincerely,
John Nissen, MA (Cantab) Natural Sciences, Director of Cloudworld Ltd
Email jn@cloudworld.co.uk for correspondence

Other signatories
Stephen Salter, Emeritus Professor of Engineering, Edinburgh University
Peter Wadhams, Professor of Ocean Physics, Head of the Polar Ocean Physics Group, Cambridge University
Gregory Benford, Professor of Physics, University of California, Irvine
John Gorman, MA (Cantab), Chartered Engineer MIMechE, MIET - UK
Colin John Baglin, B.Eng. M.Sc. C.Eng. M.I.Mech.E.
Veli Albert Kallio, FRGS, FIPC Co-Ordinator, Greenland Ice Stability Project
Dr. Brian Orr, PhD control engineering, j.mp/BrianOrr
Tom Barker, BSc PhD, School of Environmental Sciences, University of Liverpool
Nicholas Maxwell, Emeritus Reader, University College London; author - j.mp/NickMaxwell
Donald A. Grinde, Jr., Professor and Chair, Department of American Studies
SUNY at Buffalo - americanstudies.buffalo.edu
Sam Carana, contributor to Feebate.net and geo-engineering.blogspot.com

References
[1] Arctic sea ice decline: Faster than forecast, Stroeve et al, May 2007
http://www.smithpa.demon.co.uk/GRL%20Arctic%20Ice.pdf
[2] NSIDC daily images - National Snow and Ice Data Center, Boulder, Colorado
Reference image below dated June 24, 2010. For updates, see current daily image.
[3] Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS), University of Washington.
Original reference image dated May 30, 2010. Image below is dated June 18, 2010.



As NOAA reports that the May 2010 global temperature was the warmest on record, sea ice extent remains well below the 2007 record low, as shown on above NSIDC image.



Arctic Sea Ice Volume Anomaly calculated using the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS), University of Washington.

Monday, March 9, 2009

Open letter to Dr Pachauri

Climate Congress, Copenhagen, 10-12 March, 2009 

Open letter to Dr Rajendra K. Pachauri, IPCC chair


Dear Dr Pachauri,

The Climate Congress presents an important opportunity to present all facets of the current situation, explore the ramifications, and suggest appropriate actions. The aim must be, as far as possible, to address the threat of a disastrous multi-metre rise in sea level and catastrophic multi-degree rise in temperature – whenever they might occur.

We would like to suggest a rather simple division of the problem/solution domain:


Part A: Emissions reduction

About: Reducing emissions of greenhouse gases into the atmosphere.

Target: Achieve near-zero carbon economies throughout the world by end century.

Difficulties: International agreement, life-style changes, high cost.

Rationale: Long-term sustainability.


Part B : Carbon stock management

About: Removing CO2 from the atmosphere by various means.

Target: Reduce levels below 350 ppm over next three decades.

Difficulties: May involve change in agricultural practice, worldwide. Side-effects may be difficult to anticipate.

Rationale: Reduce CO2 climate forcing below its current level, halt ocean acidification and protect carbon sinks.


Part C : Heat transfer and radiation management

About: Mainly about albedo engineering and solar radiation management.

Priority target: Cool the Arctic sufficient to halt retreat of Arctic sea ice within three years.

Difficulties: Seen as tampering with the environment, and therefore intrinsically dangerous; but cost is low and side-effects should be manageable.

Rationale: Reduce risk of massive methane discharge and stabilise the Greenland ice sheet.

International focus has been almost entirely on Part A until recently, when it has been realised that: 
(1) it is proving extremely difficult to achieve reductions; 
(2) the current trend is towards IPCC’s worst case scenario; 
(3) lifetime of CO2 had been under-estimated – even if anthropogenic greenhouse gases could be stopped overnight, the existing gas levels will live on in the atmosphere for centuries, causing the global temperature to continue to rise many degrees; 
(4) global warming of more than 2 degrees could be disastrous; 
(5) tipping points could be reached much sooner than expected. It is generally recognised that the underlying primary cause of global warming is the excess of CO2 in the atmosphere. If emissions reduction can’t reduce it quickly enough, then we have to resort to some form of geoengineering – or more specifically carbon stock management – see Part B. 

Furthermore, ocean acidification is becoming dangerous, and this can only be tackled by removing CO2 from the atmosphere. So, within a decade or two, carbon stock management could become essential, and we should be doing large-scale experimentation now. 

But the actions of Part A and Part B cannot prevent tipping points driven by positive feedback on temperature. Emissions reduction and carbon stock management cannot produce a cooling effect – certainly not on the time-scales we are talking about. We have to resort to other kinds of geoengineering, hence Part C. 

As regards tipping points, our perception of the situation has changed fundamentally since the dramatic retreat of Arctic sea ice in September 2007. The IPCC had chosen to ignore potential tipping points, as being too difficult to model or lacking reliable data. 

But now some experts are talking about possible summer disappearance of sea ice within a decade [1], and this possibility is even mentioned in the introduction to Session 1 of the Congress [2]: “Sea ice is changing and the sea ice in the northern polar ocean has retreated in the last few years and might totally disintegrate during the next decade.” Sea ice disappearance will accelerate Arctic warming which could trigger the release of vast amounts of methane from permafrost (leading to many degrees of global warming) and/or destabilise the Greenland ice sheet (leading to many metres of sea level rise). 

There now appears no other possibility to save the Arctic sea ice than to cool the Arctic region, by reflecting more sunlight back into space. There are two prime candidates for this: stratospheric sulphate aerosols and marine cloud brightening [3]. The former involves the injection of a H2S or SO2 high in the stratosphere, where it reacts to form microscopic droplets of sulphuric acid which scatter sunlight efficiently. This mimics the effect of a volcano like Pinatubo, which cooled the planet for two years from its sulphur emissions into the stratosphere. The latter – the brightening of marine clouds – involves producing a very fine spray of sea water from ships which sail underneath low-lying cumulus clouds, such that some of the spray wafts upwards, brightening the clouds and reflecting light back into space. 

Modeling suggests that each of these cooling technologies should be effective, affordable, fast acting, easily reversible and reasonably safe. If we can save the Arctic sea ice, then we may be able to avoid other tipping points such as the methane release from permafrost. Such action buys time while we reduce CO2 levels and avoid other catastrophes such as from ocean acidification. On the other hand, if we do not act with the necessary urgency, we may soon find ourselves beyond the point of no return: doomed both to many metres of sea level rise and to spiraling temperatures, way above 6 degrees this century – temperatures for which the very survival of our civilization would be in question. 

- John Nissen Email: jn@cloudworld.co.uk for correspondence 
- Stephen Salter Professor of Engineering, University of Edinburgh John Latham http://www.mmm.ucar.edu/people/latham/ 
- Oliver Wingenter Professor of Atmospheric Chemistry and Climate Change, New Mexico Institute of Mining and Technology 
- Peter Read Hon. Research Fellow, Massey University Centre for Energy Research 
- Andrew Lockley, London UK Former director of Friends of the Earth ENWI 
- John Gorman MA (Cantab), London, UK 
- Sam Carana, contributor to feebate.net sam.carana@gmail.com

References:

[1] Climate Safety report, which can be downloaded from: 
http://climatesafety.org/

[2] Climate Congress, Session 1, in: 

Wednesday, December 24, 2008

heat-reflecting sheets

Engineers Takayuki Toyama of company Avix Inc in Kanagawa, Japan, and Alan Stainer of Middlesex University Business School, London, UK, suggest that, to combat global warming, heat-reflecting sheets could be installed in arid areas. This would not only reflect much of the sun's heat back into space, but could also help fight desertification. They add that the same approach might also be used to cover areas of the oceans to increase the Earth's total heat reflectivity.

The team's calculations suggest that covering an area of a little more than 60,000 square kilometres with reflective sheet, at a cost of some $280 billion, would result in net cooling, if there would be no reduction in carbon dioxide emissions.

http://groups.google.com/group/geo-engineering/browse_thread/thread/89da63d8ebef3242

Wednesday, December 17, 2008

Combat Global Warming with Evaporative Cooling

To combat global warming, wind turbines along the coastline could be used for the dual purposes of generating electricity at times when there is wind and evaporating water at times when there is no wind. Just a small breeze over the water can give the top water molecules enough kinetic energy to overcome their mutual attraction, resulting in evaporation of water and associated cooling of both water and air. The evaporation will give some cooling effect, but the real impact on global warming will come from albedo change. When there's much wind at night, offshore wind turbines could produce more energy than is needed on the grid. Such surplus power could be stored and - at times when there's little wind - used to pump up sea water and have this sprayed by the turbines as a fine mist over the water. This spray will contain tiny particles of sea-salt that get sucked up into the air, especially when there's little wind and sunshine causes rising currents of air. These little salt particles will attract further droplets of water from the surrounding air, forming clouds that are lighter in color from space than sea water (see albedo comparison below, from Wikipedia).



In early 2006, I wondered to what extent such increased cloud coverage could mitigate global warming. On the one hand, the extra clouds will reflect more sunlight back into space, but on the other hand water vapor is itself a greenhouse gas. While the albedo difference between clouds and sea water is obvious, some of the evaporated water could rise higher up into the atmosphere and increase humidity of cirrus clouds at high altitudes, thus trapping the heat underneath and heating up Earth even further through the greenhouse effect. Also, such evaporation could cause unwanted salty rain to fall over land.

Has anyone done any modeling on this?
 
Cheers! 
Sam Carana.