ONE TOWN SQUARE: at the intersection of peak oil, climate change, and land use

A study published in the September issue of the Journal of the Geological Society found that increasing CO2 levels are causing foram diversity to plummet:

A unique ‘natural laboratory’ in the Mediterranean Sea is revealing the effects of rising carbon dioxide levels on life in the oceans. The results show a bleak future for marine life as ocean acidity rises, and suggest that similar lowering of ocean pH levels may have been responsible for massive extinctions in the past.

Rising carbon dioxide levels acidify the ocean, which has a particularly devastating effect on organisms that have calcium carbonate shells, like Foraminifera. The study, published in the September issue of the Journal of the Geological Society, found that increasing CO2 levels caused foram diversity to fall from 24 species to only 4. The study found a tipping point occurs at mean pH 7.8, the pH level predicted for the end of this century.

Forams record past events in the geological record. The Paleocene-Eocene Thermal Maximum (PETM), 55 million years ago, was a period of massive carbon release and rapid warming, accompanied by extinctions in marine life.

This statement by study co-author Dr. Jason Hall-Spencer in the Geological Society’s press release is not optimistic:

Our natural laboratory provides a glimpse into the future of our oceans.

Joseph Romm at Climate Progress has posted this chart showing trends in ocean CO2 concentrations and pH at one sampling station off Hawaii.

Romm also points out that the disappearance of forams has grave implications for the rest of the food chain.

For an analysis of what that could mean, see 2009 Nature Geoscience study concludes ocean dead zones “devoid of fish and seafood” are poised to expand and “remain for thousands of years.”

A study published in the journal Global Change Biology reports the discovery of very similar colonies of bryozoans – animals that anchor themselves to the seabed – in both the Ross and Weddell Seas.

The bryozoans, sometimes called moss animals, are often microscopic as individuals but form colonies that can look like corals or some seaweeds. Those found were unlike others around the current coast of Antarctica.

So,what’s the big deal?

Bryozoans are largely static and their larvae, dispersed by currents, are short-lived and quickly sink. How is it possible that two virtually identical populations came to exist 2400 kilometers apart, separated by the 2 kilometre thick West Antarctic ice sheet?

An article at ABC News in Science quotes lead author David Barnes:

The most likely explanation of such similarity is that this ice sheet is much less stable than previously thought and has collapsed at some point in the recent past. And if the West Antarctic ice shelf has been lost in recent times we have to re-think the possibility of loss in future with climate change.

If the ice were gone a passage would become open through which currents could carry the larvae between the two seas.

Melting of the West Antarctica ice cap would raise world sea levels by between 3.5 and 5 meters. In a brief warm period about 125,000 years ago, world sea levels were about five meters higher than today and temperatures probably at least 4°C warmer.

A good friend recently asked me why I give so much attention to news about Arctic sea ice extent at this blog, saying he just glosses over posts on this subject.

Here’s the reason: the area of sea ice cover is an important, amplifying climate feedback. Loss of sea ice is a cause of concern because as the area of ice decreases, increased absorption of sunlight by the darker ocean causes more sea ice melting. As this graph from Makiko Sato & James Hansen’s new blog shows, Arctic sea ice extent has been declining steadily . . .

. . . as has sea ice volume. What ice remains is getting thinner.

It’s not just sea ice that is melting. Ice sheets are shrinking too, both in Greenland and in Antarctica.

And the ice loss over the last few years has been at a time of minimum solar irradiance. Solar irradiance is now once again on the upswing.

It seems likely that September Arctic sea ice may be all but gone within a few decades – or perhaps even sooner. What does less Arctic sea ice mean for Earth’s weather patterns?

NASA is predicting loss of summer sea ice will mean more severe winter storms in the northern hemisphere – a prediction which is already being borne out.

Following Arctic sea ice extent is fascinating because it shows that global warming is not something to worry about in the future. Global warming is here and now, and is already affecting us in our daily lives. What’s worrisome is that the impacts will only get more severe. By the time the impacts are bad enough to get our attention, it will be too late – the damage will already have been done. Under the best-case scenario it will take Earth a thousand years or more to recover. Under the worst-case scenario, Earth will flip into a different, stable climate regime which won’t be hospitable to human existence.

Above: cumulative annual area changes for 34 of the widest Greenland ice sheet marine-terminating outlets. Source: Byrd Polar Research Center.

Location of the successive calving fronts of the Jakobshavn Isbrae glacier between 1851 and 2009, overlain on a Landsat image from 7/29/2009. Source: NASA/Goddard Space Flight Center Scientific Visualization Studio. Historic calving front locations courtesy of Anker Weidick and Ole Bennike, Geological Survey of Denmark and Greenland.

Microscopic life crucial to the marine food chain is dying out. The consequences could be catastrophic.

So reads the headline of an article in the U.K. Independent reporting on new research published in the journal Nature. The study, titled Global phytoplankton decline over the past century, finds there has been a 40% decline in the ocean’s phytoplankton over the last 100 years – and global warming is to blame.

The microscopic plants that support all life in the oceans are dying off at a rate of about 1% per year. The decline is related to rising sea surface temperatures.

According to the Independent, the scientists said if the findings are confirmed by further studies, the decline in phytoplankton will represent the single biggest change to the global biosphere in modern times, even bigger than the destruction of the tropical rainforests and coral reefs. Phytoplankton are microscopic marine organisms capable of photosynthesis, just like terrestrial plants. They float in the upper layers of the oceans, provide much of the oxygen we breathe and account for about half of the total organic matter on Earth. Phytoplankton are the basis of life in the oceans and are essential in maintaining the health of the oceans. A 40% decline would represent a massive change to the global biosphere.

The press release explains that in warmer oceans, the water becomes stratified, with warmer water on top of colder deeper water. Nutrients which are normally replenished by upwelling colder water are cut off, and the photosynthesizers living in the surface waters starve to death.

Rising sea surface temperatures were negatively correlated with phytoplankton growth over most of the globe, especially close to the equator. Phytoplankton need both sunlight and nutrients to grow; warm oceans are strongly stratified, which limits the amount of nutrients that are delivered from deeper waters to the surface ocean. Rising temperatures may contribute to making the tropical oceans even more stratified, leading to increasing nutrient limitation and phytoplankton declines.

Dave Cohen points out we’re caught in a nasty downward spiral:

It is clear that we have a disastrous positive feedback loop at work here, in which warmer surface water supports fewer phytoplankton, which then take up less CO₂ from the atmosphere, which causes the surface water to warm some more due to the greenhouse effect, etc.

Here’s the abstract of the Nature article:

In the oceans, ubiquitous microscopic phototrophs (phytoplankton) account for approximately half the production of organic matter on Earth. Analyses of satellite-derived phytoplankton concentration (available since 1979) have suggested decadal-scale fluctuations linked to climate forcing, but the length of this record is insufficient to resolve longer-term trends. Here we combine available ocean transparency measurements and in situ chlorophyll observations to estimate the time dependence of phytoplankton biomass at local, regional and global scales since 1899. We observe declines in eight out of ten ocean regions, and estimate a global rate of decline of ~1% of the global median per year. Our analyses further reveal interannual to decadal phytoplankton fluctuations superimposed on long-term trends. These fluctuations are strongly correlated with basin-scale climate indices, whereas long-term declining trends are related to increasing sea surface temperatures. We conclude that global phytoplankton concentration has declined over the past century; this decline will need to be considered in future studies of marine ecosystems, geochemical cycling, ocean circulation and fisheries.

The National Oceanic and Atmospheric Administration (NOAA) has released the 2009 State of the Climate report, which concludes the scientific evidence that our world is warming is unmistakable. The past decade was the warmest on record and that the Earth has been growing warmer over the last 50 years.

Human society has developed for thousands of years under one climatic state, and now a new set of climatic conditions are taking shape. These conditions are consistently warmer, and some areas are likely to see more extreme events like severe drought, torrential rain and violent storms.

Deke Arndt, co-editor of the report and chief of the Climate Monitoring Branch of NOAA’s National Climatic Data Center, is quoted in NOAA’s press release:

The temperature increase of one degree Fahrenheit over the past 50 years may seem small, but it has already altered our planet. Glaciers and sea ice are melting, heavy rainfall is intensifying and heat waves are more common. And, as the new report tells us, there is now evidence that over 90 percent of warming over the past 50 years has gone into our ocean.

Regarding warming oceans, the report says warming has been observed as far as 6,000 feet below the surface, but most of the heat is accumulating in the oceans’ near-surface layers. The implications of a warming ocean are considerable. First, because water expands as it warms, ocean heating is responsible for much of the observed sea-level rise (melting of land-based ice is responsible for the rest). Further, the oceans will hold the heat they’ve accumulated because they warm and cool much more slowly than air – meaning the impacts of warming will continue to be felt long after greenhouse gas emissions peak and begin to decline, should humans ever manage to muster the wisdom and the will to make that happen.

The National Oceanic and Atmospheric Administration reports the global combined land and ocean surface temperature average for May was the warmest on record. The globally averaged temperature for both land and ocean surfaces was 0.69°C (1.24°F) above the 20^th century average of 14.8°C (58.6°F).

May 2010 Blended Land and Sea Surface Temperature Anomalies in degrees Celsius

The combined global land and ocean surface temperature during March–May 2010 was 14.4°C (58.0°F) and ranked as the warmest such period on record, 0.73°C (1.31°F) above the 20^th century average of 13.7°C (56.7°F).

March 2010 – May 2010 Blended Land and Sea Surface Temperature Anomalies in degrees Celsius

The warmest anomalies occurred over eastern and northern North America, eastern Brazil, northern Africa, eastern Europe, and southern Asia. See the deep red dots along the land masses of the Arctic and in southern Greenland and the eastern U.S. and Canada. Anomalously cool conditions were present over eastern Asia and the western United States.

Looks to be a long, hot summer.

May Global Hemisphere plot

The National Snow and Ice Data Center (NSIDC) reports that by the end of May, Arctic ice extent had fallen to near the 2006 level, the lowest in the satellite record for the end of that month.

NSIDC explains why Arctic ice went so rapidly from near normal to approach record lows:

[S]everal regions of the Arctic experienced a late-season spurt in ice growth. As a result, ice extent reached its seasonal maximum much later than average, and in turn the melt season began almost a month later than average. As ice began to decline in April, the rate was close to the average for that time of year. In sharp contrast, ice extent declined rapidly during the month of May. Much of the ice loss occurred in the Bering Sea and the Sea of Okhotsk, indicating that the ice in these areas was thin and susceptible to melt. Many polynyas, areas of open water in the ice pack, opened up in the regions north of Alaska, in the Canadian Arctic Islands, and in the Kara and Barents and Laptev seas.

The polynyas are clearly visible in high-resolution passive microwave images from the Advanced Microwave Sounding Radiometer (AMSR-E) aboard NASA’s Aqua satellite. What do current ice conditions mean for the minimum ice extent this fall? It is still too soon to say: although ice extent at present is relatively low, the amount of ice that survives the summer melt season will be largely determined by the wind and weather conditions over the next few months.

Analysis from scientists at the University of Washington shows that ice volume has continued to decline precipitously.

Joseph Romm comments at Climate Progress on a presentation by Wieslaw Maslowski of the Naval Postgraduate School, one of the country’s leading experts on the Arctic, indicating the Arctic is in a death spiral.  By 2016 (+/- 3 yrs) the Arctic will be essentially ice-free by the end of the melt season – decades ahead of the projections in the 2007 IPCC report.

And here’s the latest multi-year chart of Arctic ice extent from the Japan Aerospace Exploration Agency website.

The National Snow and Ice Data Center reports that, after a late start, Arctic sea ice extent has now dipped below 2007 levels at this stage of the melt season. 2007 is the year Arctic sea ice reached its record low extent.

The Japan Aerospace Exploration Agency (JAXA) has a terrific graphic on its website showing multiple years of Arctic ice extent. As you can see, it’s much too early to predict that 2010 will see a new record low, although conditions in the Arctic such as areas of open water in the pack ice and broad areas of more scattered ice cover indicate that the ice may be posed to retreat rapidly.

The area of sea-ice cover is often defined in two ways: sea-ice “extent” and sea-ice “area.” Sea ice extent is defined as the areal sum of sea ice covering the ocean (sea ice + open ocean), whereas the “area” definition counts only sea ice covering a fraction of the ocean (sea ice only). Thus, the sea-ice extent is always larger than the sea-ice area.

Regardless of ice extent, Arctic ice volume continues to hit record lows.

A new paper in the journal Nature titled Robust warming of the global upper ocean concludes that the world’s oceans have been warming more than previously thought – and more than even climate models were suggesting.

RealClimate has posted this graph showing the measured warming as compared to previous and model estimates:

Basically, if the total flux of energy entering the Earth’s atmosphere is greater than energy losses, then has to go somewhere – and that somewhere is mainly the ocean. Other reservoirs for this excess energy, like the land surface or melting ice, are much smaller and are for most purposes negligible.

An article about the study by Jason Socrates Bardi quotes Kevin Trenberth of the National Center for Atmospheric Research in Boulder, Colorado (Trenberth was not involved with the study):

Ninety percent of the energy [trapped by increased greenhouse gases] goes into the ocean. It’s important to track this in order to properly understand what is happening in the climate system. If you dump heat in the ocean and it gets moved around and reappears somewhere, it has consequences in terms of the weather patterns.

Another new study in the journal Oceanography titled The Volume of Earth’s Ocean finds the Earth’s ocean is smaller  than the most recent published estimates, by a volume equivalent to 500 times the Great Lakes or five times the Gulf of Mexico. The study’s authors used satellite altimetry data to better measure ocean depth and thus to more accurately estimate the ocean’s volume.

NOAA says the combined global land and ocean surface temperature was the warmest on record for both April and for the period from January-April.

Additionally, last month’s average ocean surface temperature was the warmest on record for any April, and the global land surface temperature was the third warmest on record.

April 2010 was the 302nd consecutive month with average global surface (land + ocean) temperature above the 20th century average.  The last month with an average global surface (land + ocean) temperature below the 20th century average was February 1985 -  over 25 years ago.

Rising temperatures are being felt in the Arctic. While Antarctic sea ice extent in April was near average, just 0.3 percent below the 1979-2000 average, Arctic sea ice extent has been plunging in May. The pace of ice extent decline is now catching up to the record-setting pace set in 2007. The record low minimum extent occurred September 16, 2007.

While Arctic ice extent in 2008 and 2009 failed to reach the record low of 2007, Arctic ice volume continues to decline year over year.

The record low for Arctic ice volume set in September 2009 at 5,800 km^3 or 67% below its 1979 maximum (for the period 1979-2009).

Things are warming up in the incubator of hurricanes, too.

Jeff Masters explains the significance at WunderBlog:

When SSTs [sea surface temperatures] in the MDR are much above average during hurricane season, a very active season typically results (if there is no El Niño event present.) SSTs in the Main Development Region (10°N to 20°N and 20°W to 85°W) were an eye-opening 1.46°C above average during April. This is the third straight record warm month, and the warmest anomaly measured for any month–by a remarkable 0.2°C. The previous record warmest anomalies for the Atlantic MDR were set in June 2005 and March 2010, at 1.26°C.

The high April SST anomaly does not bode well for the coming hurricane season. The three past seasons with record warm April SST anomalies all had abnormally high numbers of intense hurricanes. Past hurricane seasons that had high March SST anomalies include 1969 (0.90°C anomaly), 2005 (1.19°C anomaly), and 1958 (0.97°C anomaly). These three years had 5, 7, and 5 intense hurricanes, respectively. Just two intense hurricanes occur in an average year. The total averaged activity for the three seasons was 15 named storms, 11 hurricanes, and 6 intense hurricanes (an average hurricane season has 10, 6, and 2.) Both 1958 and 2005 saw neutral El Niño conditions, while 1969 had a weak El Niño.

The SSTs are already as warm as we normally see in July between Africa and the Caribbean[.]

The current El Niño is fading fast – a transition to ENSO-neutral conditions is expected by June 2010. Hurricanes may soon be piling on to the Gulf’s oil woes.

A new paper in the Proceedings of the National Academy of Sciences (PNAS) concludes there is a “small” (order 5%) risk that global warming will render a large fraction of the planet uninhabitable – like, being outside for any length of time would result in death.

Stuart Staniford at Early Warning has conveniently posted a couple of maps from the paper (which would otherwise cost you $10 to get a peak at). First, today’s world.

Currently, the inland Amazon and northern India are pretty uncomfortable, with the eastern US, northern China, and much of Australia not far behind.

Right now, we are tracking above the worst case IPCC scenario (which, if you remember, does not include feedback loops such as the Arctic releasing methane).  If we don’t do anything about climate change, we could get to about two doublings by the end of the century (over pre-industrial levels of 280ppm of CO₂). With the caveat that there is a great deal of uncertainty regarding Earth’s climate sensitivity, what might that world look like ?

Most of the world’s major population centers will be uninhabitable outdoors – meaning people would drop dead – during heat waves.

Of course, this says little about the Earth’s capability to support agriculture under such conditions. People would drop dead of starvation long before they would drop dead of heat stroke.

The National Snow and Ice Data Center (NSIDC) reports while Arctic sea ice extent throughout April was near the 1979 – 2000 average (and the highest in the past decade), much of the ice is full of open areas (called pulynyas); much of the thicker, multi-year ice has been pushed south along the coast of Greenland toward the warm waters of the North Atlantic where it will melt during the summer; and Arctic air temperatures have remained persistently warmer than average throughout the winter and early spring season.

During April, Arctic sea ice extent declined at a steady pace, remaining just below the 1979 to 2000 average. Ice extent for April 2010 was the largest for that month in the past decade. At the same time, changing wind patterns have caused older, thicker ice to move south along Greenland’s east coast, where it will likely melt during the summer. Temperatures in the Arctic remained above average.

The very late maximum ice extent, on March 31, means that the melt season started almost a month later than normal. This graph shows that ice extent has now begun to plunge.

The Polar Science Center at the University of Washington reports total Arctic ice volume for March 2010 was the lowest over the 1979-2009 period and 38% below the 1979 maximum.

Melting sea ice has dramatically accelerated warming in the Arctic, where temperatures have risen faster in recent decades than the global average, according to a new study titled The central role of diminishing sea ice in recent Arctic temperature amplification.

While itself a consequence of climate change, the shrinking Arctic ice cap is contributing to a positive feedback loop in which global warming and loss of ice reinforce each other. White sea ice reflects most of the incoming sunlight back into space. But when the ice melts, more heat is absorbed by the darker water, which in turn heats the atmosphere above it.

An APF story about the study quotes study co-author James Screen:

It was previously thought that loss of sea ice could cause further warming. Now we have confirmation this is already happening.

The findings show that the main driver of  “polar amplification” – warming in excess of the global average – is shrinking ice cover, rather than increased cloudiness or changes in ocean and atmospheric circulation.  The study’s findings also suggest that current forecasts underestimate the degree to which the polar region could heat up in the future.

A new report from the U.S. Environmental Protection Agency titled Climate Change Indicators in the U.S. states the extent of Arctic sea ice in 2009 was 24% below the 1979 to 2000 historical average. The area covered by ice is typically smallest in September, after the summer melting season. September 2007 had the least ice of any year on record, followed by 2008 and 2009.

The National Snow and Ice Data Center reports Arctic sea ice running only a bit below the 1979-2000 average – so far.

But the ice is thin, and it’s still early.

Here’s the abstract of the Screen  & Ian Simmonds study, published this week in the journal Nature:

The rise in Arctic near-surface air temperatures has been almost twice as large as the global average in recent decades — a feature known as ‘Arctic amplification’. Increased concentrations of atmospheric greenhouse gases have driven Arctic and global average warming; however, the underlying causes of Arctic amplification remain uncertain. The roles of reductions in snow and sea ice cover and changes in atmospheric and oceanic circulation cloud cover and water vapour are still matters of debate. A better understanding of the processes responsible for the recent amplified warming is essential for assessing the likelihood, and impacts, of future rapid Arctic warming and sea ice loss. Here we show that the Arctic warming is strongest at the surface during most of the year and is primarily consistent with reductions in sea ice cover. Changes in cloud cover, in contrast, have not contributed strongly to recent warming. Increases in atmospheric water vapour content, partly in response to reduced sea ice cover, may have enhanced warming in the lower part of the atmosphere during summer and early autumn. We conclude that diminishing sea ice has had a leading role in recent Arctic temperature amplification. The findings reinforce suggestions that strong positive ice–temperature feedbacks have emerged in the Arctic increasing the chances of further rapid warming and sea ice loss, and will probably affect polar ecosystems, ice-sheet mass balance and human activities in the Arctic.

A new study concludes that carbon sequestration is a pipe dream:

Published reports on the potential for sequestration fail to address the necessity of storing CO2 in a closed system. Our calculations suggest that the volume of liquid or supercritical CO2 to be disposed cannot exceed more than about 1% of pore space. This will require from 5 to 20 times more underground reservoir volume than has been envisioned by many, and it renders geologic sequestration of CO2 a profoundly non-feasible option for the management of CO2 emissions.

The study, titled “Sequestering carbon dioxide in a closed underground volume”  by Christene Ehlig-Economides, professor of energy engineering at Texas A&M, and Michael Economides, professor of chemical engineering at University of Houston, is published in the Journal of Petroleum Science and Engineering.

Total U.S. carbon dioxide emissions in 2007 were 6.02 billion metric tons (tonnes) including 2.16 billion tonnes from coal fired electric power generation, 2.6 billion tonnes from petroleum consumption mainly for transportation, and 1.2 billion tonnes from natural gas consumption. The EIA projects that US carbon dioxide emissions are forecast to reach 6.41 billion tonnes by 2030.

The Kyoto Protocol aims to keep the global temperatures from rising more than 2 degrees Celsius over pre-industrial levels and aims at stabilizing CO2 concentrations below 550 ppm – a target which scientists now believe is completely unrealistic.  Keeping CO2 levels below 350 ppm, perhaps far below, is necessary to maintain Earth’s climate as it has been during the time human civilization has developed.

If we’re to save Earth’s climate, the evidence is growing that our only hope is that oil runs out quickly and that we can muster the will to stop burning coal before we destroy ourselves.

Evidence from an Antarctic geological research drilling program known as ANDRILL suggests that the vast East Antarctic Ice Sheet, which holds at least four-fifths of the continent’s ice, is more susceptible to melting than previously thought and that an abrupt shrinkage of its ice sheets at some greenhouse gas threshold is possible, perhaps beginning within in this century.

The southern McMurdo Sound core yielded clear evidence of some 74 cycles of ice sheet buildup and retreat during a 6-million-year stretch starting in the Miocene Epoch some 20 million years ago. According to geologist Robert DeConto of the University of Massachusetts, Amherst, the policy implications are grim, as many population centers worldwide are within a few meters of sea level.

Our models may be dramatically underestimating how much worse it’s going to get. We’re seeing ice retreat faster and more dramatically than any model predicts.

The answer to the puzzling disparity between model predictions and the core data could lie in an erroneous assumption about Antarctica itself. Some parts of the land underlying the East ice sheet might be much lower than currently believed. As warming oceans strip away the surrounding ice shelves, significant chunks of the ice sheet could slide into the ocean.

A prior core, extracted from the McMurdo Ice Shelf between October 2006 and January 2007, indicated that the West Antarctic Ice Sheet has frequently advanced and retreated.

Natural gas may not be nearly as “clean” as we thought. Here’s the opening paragraph from a new study by Cornell University Professor Robert W. Howarth titled Preliminary Assessment of the Greenhouse Gas Emissions from Natural Gas obtained by Hydraulic Fracturing.

Natural gas is being widely advertised and promoted as a clean burning fuel that produces less greenhouse gas emissions than coal when burned. While it is true that less carbon dioxide is emitted from burning natural gas than from burning coal per unit of energy generated, the combustion emissions are only part of story and the comparison is quite misleading. A complete consideration of all emissions from using natural gas seems likely to make natural gas far less attractive than oil and not significantly better than coal in terms of the consequences for global warming. [Bold in original.]

Considering the release during combustion alone, greenhouse gas emissions from burning natural gas average 13.7 g C of CO2 per million joules of energy compared to 18.6 for gasoline, 18.9 for diesel fuel, and 24.0 for bituminous coal. Additional emissions of greenhouse gas occur during the development, processing, and transport of natural gas (due to the use of fossil fuels to build pipelines, truck water, drill wells, make the compounds used in drilling and fracturing, and treat wastes, and the loss of carbon-trapping forests). Howarth estimates that such emissions are at least one third of those released during combustion, compared to about 8% for gasoline and diesel. But the leakage of methane gas during production, transport, processing, and use of natural gas is the major culprit. Methane is by the far the major component of natural gas, and it is a powerful greenhouse gas: 72-times more powerful than is CO2 per molecule in the atmosphere.

Hydrofracking (high-volume, slick water hydraulic fracturing) is much worse than conventional methods of extracting natural gas.

A first attempt at comparing the total emissions of greenhouse gas emissions from HVSWHF obtained natural gas suggests that they are 2.4-fold greater than are the emissions just from the combustion of the natural gas. This estimate is highly uncertain, but is likely conservative, with true emissions being even greater. When the total emissions of greenhouse gases are considered, Greenhouse gas emissions from HVSWHF-obtained natural gas are estimated to be 60% more than for diesel fuel and gasoline. HVSWHF-obtained natural gas and coal from mountain-top removal probably have similar releases.

Howarth cautions that society should be wary of claims that natural gas is a desirable fuel in terms of the consequences on global warming. He urges us instead to rapidly move towards an economy based on renewable fuels.

The world’s water cycle has already intensified due to global warming. That’s the conclusion of a new study to be published in the American Journal of Climate.

The ocean’s average surface temperature has risen around 0.4ºC since 1950. As the near surface atmosphere warms it can evaporate more water from the surface ocean and move it to new regions to release it as rain and snow.

The study, co-authored by CSIRO scientists Paul Durack and Dr Susan Wijffels, shows the surface ocean beneath rainfall-dominated regions has freshened, whereas ocean regions dominated by evaporation are saltier. The paper also confirms that surface warming of the world’s oceans over the past 50 years is penetrating into the ocean depths, changing deep-ocean salinity patterns.

The broad-scale patterns of change revealed in the study validate climate model simulations in the Intergovernmental Panel on Climate Change (IPCC)’s 4th Assessment Report.

Researchers from the Arctic Institute of North America began studying the Devon Island ice cap in 1961.

Between 1961 and 1985, the ice cap grew in some years and shrank in others, resulting in an overall loss of mass. A paper published in the March edition of the journal Arctic finds a steady decline in ice volume and area began in 1985, a decline that is now accelerating.

The High Arctic is essentially a desert with low rates of annual precipitation. There is little accumulation of snow in the winter; and cool summers, with temperatures at or below freezing, maintain snow and ice levels. Any increase of snow and ice takes years – and one warm summer can wipe out many years of growth. Though the accelerated melting trend began in 1985, the last decade has seen four years with unusually warm summers: 2001, 2005, 2007 and 2008.

Another recent study finds that ice loss from the Greenland ice sheet, which has been increasing during the past decade over its southern region, is now moving up its northwest coast. The research indicates the ice-loss acceleration began moving up the northwest coast of Greenland starting in late 2005.

The AGU press release quotes study co-author John Wahr:

When we look at the monthly values from GRACE, the ice mass loss has been very dramatic along the northwest coast of Greenland. This is a phenomenon that was undocumented before this study. Our speculation is that some of the big glaciers in this region are sliding downhill faster and dumping more ice in the ocean.

and co-author Isabella Velicogna:

These changes on the Greenland ice sheet are happening fast, and we are definitely losing more ice mass than we had anticipated. We also are seeing this trend in Antarctica, a sign that warming temperatures really are having an effect on ice in Earth’s cold regions.