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.

Dr. Jeff Masters at WunderBlog reports that both the Northwest Passage and the Northern Sea Route are now open. Data at the University of Illinois site Cryosphere Today shows it is now possible to completely circumnavigate the Arctic Ocean in ice-free waters – and this will probably continue to be the case for at least a month.

This year marks the third consecutive year–and the third time in recorded history–that both the Northwest Passage and Northern Sea Route have melted free, according to the National Snow and Ice Data Center.

The Northeast Passage opened for the first time in recorded history in 2005, and the Northwest Passage in 2007. It now appears that the opening of one or both of these northern passages is the new norm.

Here’s an updated graphic:

As this graphic from Chris Mooney’s article in New Scientist shows, ice volume has been decreasing even more precipitously than ice area.

The average volume of Arctic ice between July and September has fallen from 21,000 cubic kilometres in 1979 to 8000 cubic kilometres in 2009, a 55% decline compared with the 1979 to 2000 average. This is even faster than the decline in ice extent, which is 40% below the long-term average.

Not only has the total volume of Arctic ice continued to decline since 2007 considerably more quickly than predicted by most climate models, the rate of loss is accelerating. The Arctic Ocean may soon be essentially ice-free during the summer months. The dark ocean waters, mostly devoid of ice, would then absorb still more sunlight, further warming the overlying atmosphere during an increasingly lengthy ice-free season, reshaping weather throughout the region and well beyond it.

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.

According to the National Snow and Ice Data Center (NSIDC), neither the Northwest Passage through the Canadian Arctic nor the Northern Sea Route along the coast of Siberia are yet free of ice and open – but it’s looking like they soon will be.

A Russian gas tanker set out from Murmansk on August 14 across the Northern Sea Route, escorted by two nuclear ice breakers, and is expected to deliver its cargo of gas condensate to China by early September.

Ice in the Vilkitsky Strait is the only remaining impediment to shipping across the Northern Sea Route . . .

. . . as seen in this NSIDC graphic of sea ice extent.

While this latest graphic shows the northern route of the Northwest Passage as being open, NSIDC’s Arctic Sea Ice News reports that as of August 17 neither the northern route (Western Parry Channel) nor the southern route (Amundsen’s Passage) through the Northwest Passage were completely clear of ice.  NSIDC says that sea ice area within the northern route is currently well below the 1968 to 2000 average and almost a month ahead of the clearing that was observed in 2007. In the southern route, there is still a substantial amount of ice.

If winds push sea ice away from the entrance to M’Clure Strait, the northern route of the Northwest Passage could open again this year – if it hasn’t already.

On August 21, 2007, the Northwest Passage became open to ships without the need of an icebreaker.  The Northwest Passage opened again on August 25, 2008. In late August 2008, satellite images showed that the last ice blockage of the Northern Sea Route had melted – which would be the first time since satellite records began that both the Northwest Passage and Northern Sea Route were open simultaneously.

The Northern Sea Route was open in 2005 but closed again by 2007. A Russian nuclear icebreaker escorted a small convoy including two Western commercial vessels westward through the Northern Sea Route in 2009.

Scientists predict in a new study that fewer than one in five of the plants and animals which currently live in the world’s rainforests will still be here in 90 years time. The culprits? Climate change and deforestation.

The study, “Correlative and mechanistic models of species distribution provide congruent forecasts under climate change”, is published in the June edition of Conservation Letters, an open-access journal. Here’s the abstract:

Good forecasts of climate change impacts on extinction risks are critical for effective conservation management responses. Species distribution models (SDMs) are central to extinction risk analyses. The reliability of predictions of SDMs has been questioned because models often lack a mechanistic underpinning and rely on assumptions that are untenable under climate change. We show how integrating predictions from fundamentally different modeling strategies produces robust forecasts of climate change impacts on habitat and population parameters. We illustrate the principle by applying mechanistic (Niche Mapper) and correlative (Maxent, Bioclim) SDMs to predict current and future distributions and fertility of an Australian gliding possum. The two approaches make congruent, accurate predictions of current distribution and similar, dire predictions about the impact of a warming scenario, supporting previous correlative-only predictions for similar species. We argue that convergent lines of independent evidence provide a robust basis for predicting and managing extinctions risks under climate change.

By 2100, climate change and deforestation could have altered two-thirds of the rainforests in Central and South America and about 70% in Africa. The Amazon Basin alone could see changes in biodiversity for 80% of the region.

A U.K. Telegraph article about the study quotes Daniel Nepstad, senior scientist at the Woods Hole Research Center, which studies climate change in Massachusetts:

This study is the strongest evidence yet that the world’s natural ecosystems will undergo profound changes including severe alterations in their species composition through the combined influence of climate change and land use. Conservation of the world’s biota, as we know it, will depend upon rapid, steep declines in greenhouse gas emissions.

Battered by record heat and a drought that has destroyed millions of hectares of crops, Russia – the world’s third largest wheat exporter – has banned grain exports.

Prime Minister Vladimir Putin announced:

In connection with the unusually high temperatures and the drought, I consider it right to impose a temporary ban on the export from Russia of grain and other products produced from grain.

Putin said Russia’s policy after December 31 would be determined by the results of the harvest. Russia has slashed its 2010 grain harvest forecast to 70-75 million tonnes, compared with a harvest of 97 million tonnes in 2009.

The record heat and drought have spawned widespread wildfires. Peat bog fires outside Moscow have shrouded the capital in smog. Wheat prices have soared as Russia sizzles.

Jeff Masters at Wunder Blog reports the Russian population affected by extreme heat is at least double the population of Moscow, which is just over ten million; and the death toll in Russia from the 2010 heat wave is probably at least 15,000, and may be much higher. The only comparable heat wave in European history occurred just seven years ago in 2003, and killed an estimated 40,000 – 50,000 people, mostly in France and Italy.

Masters observes this is the worst heat wave in Russian history:

Prior to this year, the hottest temperature in Moscow’s history was 37.2°C (99°F), set in August 1920. The Moscow Observatory has now matched or exceeded this 1920 all-time record five times in the past two weeks. Temperatures the past 27 days in a row have exceeded 30°C in Moscow. Alexander Frolov, head of Russia’s weather service, said in a statement today, “Our ancestors haven’t observed or registered a heat like that within 1,000 years. This phenomenon is absolutely unique.”

Russian President Dmitry Medvedev says its time to face up to the reality of climate change:

None of us can say what the next summer will be like. The forecasts vary greatly. Everyone is talking about climate change now. Unfortunately, what is happening now in our central regions is evidence of this global climate change, because we have never in our history faced such weather conditions in the past. This means that we need to change the way we work, change the methods that we used in the past.”

Fat chance of that happening, here. No matter what the evidence, it’s business as usual, pursue growth at any cost, and let the future take care of itself.

Update: Peak Oil News has posted this great graphic showing the distribution of fires:

Scientists are saying the record heat wave in Russia and the deadly heat and flooding in Asia may become the norm rather than the exception. The Peak Oil News piece quotes Professor Michael Mann, a noted paleo-climatologist researcher:

The record heat waves we’re seeing this summer aren’t simply a random event in isolation. They are embedded in the warmest 6 month period the globe has seen in the instrumental record spanning the past 150 years. And a wealth of paleoclimate evidence suggests that the past few decades are the warmest period in at least a thousand years, and perhaps much longer.

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.

Dr Hubbard shows how soot has pock-marked the ice

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.

June 2010 was the hottest June since widespread weather recording began, according to the National Climatic Data Center.

June 2010 was the fourth consecutive month with reported warmest averaged global land and ocean temperature on record (March, April, and May 2010 were also the warmest on record). June 2010 was the 304^th consecutive month with a global temperature above the 20^th century average.

The combined global average land and ocean surface temperature for the January–June period was the warmest such period on record, 0.68°C (1.22°F) above the 20^th century average.

Jeff Masters at Wonder Blog reports nine countries have smashed all-time temperature records so far in 2010:

]S]ix nations in Asia and Africa set new all-time hottest temperature marks in June. Two nations, Myanmar and Pakistan, set all-time hottest temperature marks in May, including Asia’s hottest temperature ever, the astonishing 53.5°C (128.3°F) mark set on May 26 in Pakistan. Last week’s record in Russia makes nine countries this year that have recorded their hottest temperature in history, making 2010 the year with the most national extreme heat records.

This graph shows how global temperatures have been rising over the past 100 years:

The National Snow and Ice Data Center (NSIDC) reports the rate of ice loss in the Arctic slowed in the first half of July, primarily because of a change in atmospheric circulation as the dipole anomaly, an atmospheric pattern that dominated the Arctic in June, broke down.

The report explains:

Through much of May and June, high pressure dominated the Beaufort Sea with low pressure over Siberia. Winds associated with this pattern, known as the dipole anomaly, helped speed up ice loss by pushing ice away from the coast and promoting melt.

However, the dipole anomaly pattern broke down in early July. In the first half of July, cyclones (low pressure systems) generated over northern Eurasia tracked eastward along the Siberian coast and then into the central Arctic Ocean, where they tend to stall. This cyclone pattern is quite common in summer. The low-pressure cells have brought cooler and cloudier conditions over the Arctic Ocean. They have also promoted a cyclonic (anticlockwise) sea ice motion, which acts to spread the existing ice over a larger area. All of these factors likely contributed to the slower rate of ice loss over the past few weeks.

In the last few days, high pressure has started to build again in the Beaufort Sea, but whether this will continue remains to be seen.

Still, Arctic sea ice extent at this time is the second lowest ever recorded, as seen in this chart from the Japan Aerospace Exploration Agency website, IJIS.

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 Arctic sea ice declined at the fastest rate ever recorded in June, and the average ice extent in June was the lowest in the satellite data record (from 1979 to 2010).

The previous record for the fastest rate of June decline was set in 1999. The linear rate of monthly decline for June over the 1979 to 2010 period is now 3.5% per decade.

Whether or not 2010 will see a new record low set for Arctic sea ice extent depends upon weather patterns. NSIDC explains:

The record low ice extent of September 2007 was influenced by a persistent atmospheric pressure pattern called the summer Arctic dipole anomaly (DA). The DA features unusually high pressure centered over the northern Beaufort Sea and unusually low pressure centered over the Kara Sea, along the Eurasian coast. In accord with Buys Ballot’s Law, this pattern causes winds to blow from the south along the Siberian coast, helping to push ice away from the coast and favoring strong melt. The DA pattern also promotes northerly winds in the Fram Strait region, helping to flush ice out of the Arctic Ocean into the North Atlantic. The DA pattern may also favor the import of warm ocean waters from the North Pacific that hastens ice melt.

June 2010 saw the return of the DA, but with the pressure centers shifted slightly compared to summer 2007. As a result, winds along the Siberian coastal sector are blowing more from the east rather than from the south. Whether or not the DA pattern persists through the rest of summer will bear strongly on whether a new record low in ice extent is set in September 2010.

A report in Science magazine brings together dozens of studies that collectively paint the dismal picture that the deterioration of ocean health is rapidly approaching the point where it may be irreversible.

Ove Hoegh-Guldberg, director of the Global Change Institute at the University of Queensland in Australia and a co-author of the report, says:

This is further evidence we are well on our way to the next great extinction event.

Important conclusions in the report, titled The Impact of Climate Change on the World’s Marine Ecosystems, include:

• The average temperature of the upper level of the oceans has increased more than 1 degree Fahrenheit during the past 100 years, and global ocean surface temperatures in January were the second warmest ever recorded for that month.
• Though the increase in acidity is slight, it represents a “major departure” from the geochemical conditions that have existed in the oceans for hundreds of thousands if not millions of years.
• Nutrient-poor “ocean deserts” in the Pacific and Atlantic oceans grew by 15 percent from 1998 to 2006.
• Oxygen concentrations are dropping off the Northwest U.S. coast and the coast of southern Africa, where dead zones appear regularly. There is paleontological evidence that declining oxygen levels in the oceans played a major role in at least four or five mass extinctions.
• Since the early 1980s, the production of phytoplankton, a crucial part of the food chain, has declined 6 percent, with 70 percent of the decline found in the northern parts of the oceans. Scientists also found that phytoplankton are becoming smaller.

Here’s the abstract:

Marine ecosystems are centrally important to the biology of the planet, yet a comprehensive understanding of how anthropogenic climate change is affecting them has been poorly developed. Recent studies indicate that rapidly rising greenhouse gas concentrations are driving ocean systems toward conditions not seen for millions of years, with an associated risk of fundamental and irreversible ecological transformation. The impacts of anthropogenic climate change so far include decreased ocean productivity, altered food web dynamics, reduced abundance of habitat-forming species, shifting species distributions, and a greater incidence of disease. Although there is considerable uncertainty about the spatial and temporal details, climate change is clearly and fundamentally altering ocean ecosystems. Further change will continue to create enormous challenges and costs for societies worldwide, particularly those in developing countries.

A meta-analysis published recently in the Journal of the American Planning Association finds the most important single factor in minimizing driving is to develop in existing areas of high destination accessibility – like city centers. Going back in time (or back to the future), that would be villages.

Other factors like mixed-use, street and intersection design, and block size prove to be less important than destination accessibility. Still, these factors are more important than mere density. Density is less important than land-use mix and having shops, schools, and workplaces near to where people live.

Not surprisingly, driving is found to have energy and climate implications:

The transportation outcomes . . .  vehicle miles traveled (VMT) and vehicle trips (VT), are critically linked to traffic safety, air quality, energy consumption, climate change, and other social costs of automobile use.

Figuring out a way to drive less – much, much less – is key to coming to grips with peak oil and to arresting global warming before we reach a tipping point beyond which Earth’s climate will spin out of control, resulting in an Eaarth we no longer recognize and which is no longer fit for human habitation.

The free-access analysis, Travel and the Built Environment, was authored by Reid Ewingab of the University of Utah’s Urban Land Institute; and Robert Cerverocde, University of California (Berkeley) Transportation Center, Institute of Urban and Regional Development.

Here’s the abstract:

Problem: Localities and states are turning to land planning and urban design for help in reducing automobile use and related social and environmental costs. The effects of such strategies on travel demand have not been generalized in recent years from the multitude of available studies.

Purpose: We conducted a meta-analysis of the built environment-travel literature existing at the end of 2009 in order to draw generalizable conclusions for practice. We aimed to quantify effect sizes, update earlier work, include additional outcome measures, and address the methodological issue of self-selection.

Methods: We computed elasticities for individual studies and pooled them to produce weighted averages.

Results and conclusions: Travel variables are generally inelastic with respect to change in measures of the built environment. Of the environmental variables considered here, none has a weighted average travel elasticity of absolute magnitude greater than 0.39, and most are much less. Still, the combined effect of several such variables on travel could be quite large. Consistent with prior work, we find that vehicle miles traveled (VMT) is most strongly related to measures of accessibility to destinations and secondarily to street network design variables. Walking is most strongly related to measures of land use diversity, intersection density, and the number of destinations within walking distance. Bus and train use are equally related to proximity to transit and street network design variables, with land use diversity a secondary factor. Surprisingly, we find population and job densities to be only weakly associated with travel behavior once these other variables are controlled.

Takeaway for practice: The elasticities we derived in this meta-analysis may be used to adjust outputs of travel or activity models that are otherwise insensitive to variation in the built environment, or be used in sketch planning applications ranging from climate action plans to health impact assessments. However, because sample sizes are small, and very few studies control for residential preferences and attitudes, we cannot say that planners should generalize broadly from our results. While these elasticities are as accurate as currently possible, they should be understood to contain unknown error and have unknown confidence intervals. They provide a base, and as more built-environment/travel studies appear in the planning literature, these elasticities should be updated and refined.

Continuously updated Arctic Sea Ice Volume Anomaly from PIOMAS. Daily Sea Ice volume anomalies for each day are computed relative to the 1979 to 2009 average for that day. The trend for the 1979- present period is shown in blue. Shaded areas show one and two standard deviations from the trend. Click on image for a larger version of the figure

It’s approaching the end of June, and Arctic sea ice is continuing to melt precipitously.  Arctic sea ice is shrinking at a record pace both in extent . . .

. . . and in volume:

We’ve never seen anything like current conditions in the historical record.