Now that hurricane season is upon us, we’re learning this week from forecasters that it’s supposed to be a bad one:

Weather Services International predicted 18 named storms, 10 hurricanes and five intense hurricanes, rated as Category 3 storm with winds of 110-130 mph, or greater.

NBC ran a segment (video clip) asking what impacts hurricanes might have on the oil spill.  The clip mentions, among other things, that 2010 Atlantic sea surface temperatures are the warmest on record—not a good omen when it comes to hurricane intensity.

This is, potentially, a very serious situation for the Gulf states.   If a Katrina-like storm surge were to push the oil plume onto land, we would be looking at possible oil contamination of all of the affected land areas.  Imagine parking your car in your house and opening the oil pan drain plug, letting oil leak onto the floors and out onto your driveway, lawn, and streets.  Now do that for every car and home along the Gulf Coast that could be impacted by storm surge where the oil plume is close to shore.

This has to be keeping people at EPA and the Gulf Coast up at night.   It could be an environmental pollution disaster the likes of which we have never seen—Marshes, swamps, white-sand beaches, and coastal/vacation communities becoming a giant, oil-soaked, polluted brownfield.

One would think that witnessing this kind of unprecedented environmental disaster, and the potential for worse with the impending hurricane season, would help make the case for the transition to clean energy.  Indeed, this week we have seen the oil spill mentioned by President Obama and some members of Congress as motivation for a long-term energy strategy.

Don’t hold your breath.

Even these events—as bad as they appear in real life— can be externalized from the day-to-day lives of most people in unaffected areas.  Maybe that will change as this spill gets worse and we face the possibility of oil release for another few months, but right now, there is simply not enough outrage from the public demanding change in Washington, as Bob Herbert alluded to last week.  And John Kerry is right, halting drilling on the Gulf Coast isn’t going to happen.

So where does all this leave us in terms of climate change, energy, and oil spills?

I’m pretty pessimistic these days.  I’m not sure if anything short of a severe economic energy shock that hits ordinary people hard—similar to what we saw in 2006-2007—will bring us to a tipping point.  If the U.S. returns to $4-5/gallon gasoline and home heating oil, we will start seeing environmentalists, security hawks, the energy independence crowd, green jobs advocates, and everyday citizens realign once again.  Only then will there be a coalition large and loud enough to force Washington take on the political-economic might of the fossil fuel industry and their lobbyists.

If my guess is right, then we are probably still a few years away from seeing a serious move to clean energy—not until the economic recovery is further along, economies pick up speed, and the demand for oil and oil speculation kick back into high gear, causing oil prices to spike once more.  Fortunately, this time around—unlike 2006-2007—we will have better technology, including electric cars, which will help make the leap easier and more sustained (provided that people can afford them).

The Gulf Coast is unfortunately poised to become collateral damage as we wait for more significant economic drivers to make the clean energy transition happen.

I’m lucky to have had the chance to travel along the coast from New Orleans to Tampa in the spring of 2005 before Katrina hit and now this oil spill happened.  It’s a beautiful region.  For our friends and all of the wildlife living there, let’s just hope this is a mild hurricane season and that most of the oil stays in the deep sea where it will hopefully get removed by hungry bacteria.

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Photo credit: http://www.flickr.com/photos/joiseyshowaa/2392156164/

This interesting piece by John Parker can be found in this quarter’s Intelligent Life, the lifestyle and culture magazine from The Economist.

With a seemingly distant and global challenge like climate warming, it’s been a struggle for science to convey the realities that warming is underway and that it’s likely human caused.

What would it take to persuade the 50% of Americans and others around the world who are unconvinced that warming is happening and that is has the potential to fundamentally alter our lives and experiences?  A catastrophe like sudden, major ice loss from Antarctica or Greenland?

Subtle shifts like the timing of flowers, the lengthening of spring, the migration of birds, or thawing permafrost—things we have been documenting and writing about since the 1990s— seem to happen unnoticed.

Or perhaps not, as Parker indicates…

In the Indian state of Orissa, the black-headed oriole is the messenger of spring. It appears in the villages in January to greet the season’s start and flies away to the forest in March, signalling its end. Richard Mahapatra’s mother used the oriole’s fleeting appearance to teach her son about the natural rhythms of the world. “People like my mother remember six distinct seasons,” says Mahapatra, an environmental writer who now lives in New Delhi. After spring (basanta) and summer (grishma) came the rainy season (barsha). Between autumn (sarata) and winter (sisira) came a dewy period called hemanta. Each season lasted two months and the appearance of each was marked by religious festivals. “She had precise dates for their arrival and taught me how to look for signs of each.”

Damselflies gathered thickly a week before the rains began. Markers of the monsoon, they did not cluster at other times. The open-billed stork alighted on the tamarind tree on Akshaya Trutiya, a festival which usually fell in April or May and traditionally marked the start of the agricultural year. Farmers said that if you forgot the day, the bird would remind you, so predictable was its arrival. In the Mahapatra family’s garden, the nesting of bats in the peepal tree marked the onset of winter; when the tree flowered, it was midsummer.

Lately the heralds of the seasons have become unreliable. Damselflies swarm not only in the rainy season but in winter, the driest time of year. The stork no longer appears just on Akshaya Trutiya, but at other times, too. Villagers hear the song of the oriole in summer and the rainy season, not just spring. And this, Mahapatra says, is because spring is no longer a distinct season. Instead of six periods of equal length, Orissa now has two, a brief rainy season and a burning eight-month summer. Winter is a mild transition between the two, and spring, autumn and hemanta have been relegated to little-noticed interludes of a mere week or so.

“When I return home”, says Mahapatra, “my mother mourns the death of the seasons. Her memories of Orissa’s climate are alien to the generation I belong to. For me, my childhood Orissa is dying. The state now has a new and strange climate that nobody can understand or predict.”

Read more here…

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Photo credit:  http://www.flickr.com/photos/ddsnet/ / CC BY-NC-ND 2.0

I remember driving on a freeway in Phoenix after midnight in 1990.  The temperature was a cool 102 degrees F after breaking the all-time heat record of 126 F that day.  Deserts are good at cooling off at night.  But with all of the built environment in Phoenix storing heat from the day, the sidewalks, roads, and even swimming pools felt like they were being heated.

We all have probably experienced urban heat islands—the mass of dark asphalt and concrete absorbing solar radiation and radiating it back to space as heat.  The lack of water exacerbates the situation because there is little-to-no evaporative cooling.  Waste heat from cars, machines, air conditioners, and even human bodies also heat up the air.  And the warmer it gets, the stronger the tendency to crank up the air conditioners, generating even more waste heat.

The problem is potentially large in areas like the Middle East, India, parts of Africa, and the American Southwest, where rapid urbanization in warm, dry environments has the potential to make some urban areas much warmer at night than surrounding rural areas.

In a forthcoming article in Geophysical Research Letters¹, Mark McCarthy and colleagues at the Met Office, Hadley Centre, UK used a climate model that examines what climate might look like in a doubled CO₂ world and calculates the added warming caused by urbanization and wasted heat.

Their results were eye-opening:

• Urban regions in places like the Arabian Peninsula, Iran, and India may experience night time warming by as much as 3-5 degrees C above and beyond that caused by doubled CO₂ alone.
• The number of hot nights per year (defined as temperatures in the 99th percentile of nonurban areas) increase in the following cities:
  • London: 1-2 hot nights now vs. up to 10 hot nights in 2050
  • Sydney: 1-2 hot nights now vs. up to 15 hot nights in 2050
  • Delhi: 5-10 hot nights now vs. up to 30 hot nights in 2050
  • Beijing: 3-6 hot nights now vs. up to 50 hot nights in 2050
  • Los Angeles: 8-12 hot nights now vs. up to 40 hot nights in 2050
  • Tehran: 20 hot nights now vs. up to 60 hot nights in 2050
  • Sao Paulo: <5 hot nights now vs. up to 80 hot nights in 2050
  • Lagos (Nigeria): <5 hot nights now vs. up to 150 hot nights in 2050

As mentioned in an earlier post, we only need to remember Chicago in 1995 to recall the deadly impact that heat waves can have on urban people.  And as we saw in that unfortunate example, the victims were disproportionately the elderly and African American.

Although we may not be able to mitigate this warming, basic adaptation steps should be set into motion, including re-thinking urban design, making cities more resilient to hot environments, developing better energy and technology solutions (including cooling), installing green roofs, and putting into place emergency disaster plans and social safety nets for vulnerable populations.

¹Mark McCarthy, Martin Best, and Richard Betts (2010). Climate change in cities due to global warming and urban effects Geophysical Research Letters : 10.1029/2010GL042845

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Photo Credit:

A lot of us are on the lookout for increased releases of soil carbon in northern ecosystems, which could signal the initiation of a positive feedback to warming.   Remember that more warming has the possibility of increasing decomposition of soil carbon, which causes the release of more CO₂ to the atmosphere, causing further warming (the feedback mechanism).

I was delighted to open today’s issue of Nature and see an article by one of my colleagues—Ben Bond-Lamberty (together with colleague Allison Thomson)—who completed a global assessment of soil carbon release.¹

To give you a bit of a primer, a couple of decades ago, we used to think that soils worldwide released about 60 gigatons of carbon each year.   That’s about six times the total current release of anthropogenic carbon from fossil fuels and deforestation combined.  So no small potatoes.   You can therefore think of humans as “decomposers” who release about 1/6 the amount of carbon that soil microbes do each year.

Based on a meta-analysis of 439 studies of soil carbon respiration, Ben and Allison discovered that this number has risen to about 98 gigatons (+/- 12 Gt) per year in 2008 and that it’s growing by about 0.1 gigaton per year.  Part of this is due to better estimates of global soil respiration, but as their data suggest, part of it is also a genuine upward trend.

The trend of increasing soil CO₂ release over time correlates with the late-20th-century rise in air temperatures.

Case closed on the positive feedback?  Not so fast they wisely warn us.  At face value, this change is consistent with temperature-driven increases in soil respiration.  However, Ben and Allison are right to point out that we need to be a bit careful and ask where that extra carbon is coming from.  For simplicity, we can think of two sources:

• As the positive feedback hypothesis suggests, it might be old soil carbon that is decomposing now that microbes are warmer and more active.
• However, a world with more CO₂ will also fertilize tree growth and lead to increased production of things like leaves, branches, and tree stems that fall to the ground each year.  If climate change is causing more of this “litterfall” to happen, then the increased decomposition Ben and Allison detected might simply reflect that fact there is more dead fresh litter falling onto soils around the globe.

Either possibility is interesting, but it’s really the first one that’s worrisome in terms of accelerated climate warming.  Why?  Because a jazzed-up carbon cycle (bullet #2) doesn’t really add any new carbon to the atmosphere.  If trees grow more and then that growth is released as greater soil decomposition, all we have done is made the plant uptake arrow bigger and the soil release arrow bigger.  No net change in atmospheric CO₂.

It’s hard to tell at this point if one or the other (or both) mechanisms are at play.  If it is the beginning of a climate warming positive feedback, it’s all the more imperative that we  get carbon emissions and temperatures under control quickly.

¹Bond-Lamberty, B., & Thomson, A. (2010). Temperature-associated increases in the global soil respiration record Nature, 464 (7288), 579-582 DOI: 10.1038/nature08930

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Photo Credit: One of my photos of a low-Arctic Sphagnum peat bog in Manitoba, Canada, which you can view at my Flickr site.

Most people have heard about the potential positive feedback of soil carbon on climate: As temperatures warm, soil microbes are more active and permafrost begins to thaw–both of which can hasten decomposition and the release of CO₂ to the atmosphere.  This, in turn, has the potential to accelerate warming.

A lot of us who study climate warming impacts in boreal and Arctic ecosystems are interested in this problem.  There are a few things we keep an eye on:

• How fast are temperatures warming in the Arctic?
• How fast is permafrost thawing?
• How much soil carbon is there?

All of these questions are active areas of research.  Increase any of them, and you have the possibility of strengthening the positive feedback.  The third one is particularly interesting.   The more we study and inventory soil carbon at high latitudes, the more we revise upwards the estimate of soil carbon.

Here’s an example:  The atmosphere contains about 750 gigatons of carbon.  When I was in grad school back in the early 90’s, we thought that boreal and arctic soils might have stored around 350 gigatons—about half the atmospheric content.   With the discovery of extremely carbon-rich yedoma soils in Siberia, we learned that this number might be a serious underestimate.   And as we learn more about soil carbon stored in deeper, harder-to-sample permafrost soils, we are coming to the realization that high-latitude soils may store between 1000-1700 gigatons—substantially more than the atmosphere (here’s one example).

Let’s say for illustration that the real number is 1500 gigatons.  This means that warming would only need to cause a loss of 1/2 of 1% of this soil carbon to release 7.5 gigatons—roughly the total amount of fossil fuel carbon released worldwide each year.   Thus, small changes in decomposition of a huge soil carbon pool can lead to carbon releases that rival anthropogenic emissions.

In a forthcoming issue of Global Biogeochemical Cycles,¹ Jennifer Howarth Burnham and Ronald Sletten further illustrate that the more we sample, the more this soil carbon number goes up.

Focusing on Greenland, they dug 55 soil pits and measured soil carbon.  Then, they extrapolated these estimates to the rest of the circum high Arctic by (1) linking soil carbon to certain vegetation types and (2) using satellite imagery estimates of the area of each vegetation type to estimate soil carbon for a much larger region.

Although the new number they produced is not large (12 gigatons), it is five times the previous estimate for High Arctic soils.   It’s important to note that much of the High Arctic is a polar desert with little plant growth that could contribute to soil carbon, so it’s not surprising that more of the soil carbon is farther south—in boreal and subarctic regions.

One important caveat is that they only sampled surface soils that thaw during summer and are easy to sample.  By omitting deeper permafrost soils, they probably underestimated the total.

And so we keep sampling…

¹Burnham, J. H., and R. S. Sletten (2010). Spatial Distribution of Soil Organic Carbon in Northwest Greenland and Underestimates of High Arctic Carbon Stores Global Biogeochemical Cycles : 10.1029/2009GB003660

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Photo credit:  One of my photos from the Canadian Arctic that you can view on my flickr site

This paper by Thomas Crowley is an earlier example of how climate scientists compare the relative effects of natural vs. human factors on climate over the past 1000 years.

The IPCC 2007 report projected a conservative sea level rise of about 18-59 cm by the year 2100.

Why conservative?  Because it mainly accounted for things we know are happening and can measure well—like thermal expansion of the ocean and melting of land glaciers (see here for a discussion of the Kilimanjaro example).  What it doesn’t do so well is account for all of the potential ways that the big ice sheets (Greenland and Antarctica) can contribute to sea level rise.  Things like ice flow and mass loss are generally assumed to be constant, even though recent research papers discussed in previous posts (here and here) suggest they are accelerating.

Since the publication of the IPCC report in 2007, there have been several studies suggesting that sea level rise will be 1-2 meters or more by 2100 (one example here).  One study looked at geological evidence for sea level rise during the previous interglacial period 125,000 years ago, which was 1-2 degrees C warmer than today.  Their work indicated that there was a 95% chance that sea level rose by 6 meters (22 feet).

In a forthcoming issue of Geophysical Research Letters,  Svetlana Jevrejeva and colleagues used statistical models to project sea level rise by 2100.¹ But they also did something else interesting.  They looked back several thousands of years to the most extreme events that could cause climate cooling—things like severe volcanic eruptions, which create stratospheric dust clouds that block sunlight.

If events like this were to happen again, they asked, would they cause enough cooling to be able to slow sea level rise caused by greenhouse gases?

The answer is no.  There appears to be no natural factors like vulcanism that will significantly slow greenhouse-gas-driven sea level rise that we are already committed to or future sea level rise that we may experience if we continue to emit fossil fuels.

Excerpts (emphasis mine):

• With the assumption that sea level will continue to respond over the next 100 years to the same forcings that have influenced it during the past 1000 years, we estimate 0.6 -1.6 m of global sea level rise in the 21st century using a statistical model driven by projected natural and anthropogenic forcings.
• In contrast to the 20th century sea level rise that was associated with a significant contribution of 25% from natural (solar and volcanic) forcing, 21st century sea level rise will be clearly dominated by the changes in CO2 and other greenhouse gases.
• Alternative scenarios for solar forcing with a potential decrease in solar irradiance of 1W/m2 (using the lowest level recorded throughout the last 9300 years) only produce a 10-20 cm reduction in our estimate of 21st century sea level rise.
• If we utilize the 13th century past volcanic forcing to estimate a possible (but unlikely) contribution from volcanic activity, then an almost negligible 8 cm decrease is projected in the estimated sea level rise.
• The suggested reduction of radiative forcing by injections of SO2 into atmosphere (equivalent to a Pinatubo eruption every 4 years) would be equivalent to delaying sea level rise by 12 -20 years.
• A “no changes in radiative forcing” scenario produced 16-22 cm (with lower limit of 10 cm and upper limit of 31 cm) sea level rise in the 21 century due to the inertia of the climate system, providing evidence that conditions established during the past centuries have already committed us to a considerable global sea level rise during the next 100 years.

¹Jevrejeva, S., J. C. Moore, and A. Grinsted (2010). How will sea level respond to changes in natural and anthropogenic forcings by 2100? Geophysical Research Letters : 10.1029/2010GL042947

UPDATE:  RealClimate provides more explanation of the IPCC being too cautious about sea level rise.

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Photo Credit: http://www.flickr.com/photos/gsfc/ / CC BY 2.0

One of the challenges of climate literacy is helping folks visualize fossil fuel emissions and their impacts.

Last year, Bowdoin College completed its emissions inventory and climate action plan.  We discovered that the campus emits a total of 24,000 tons of CO₂ equivalents each year.   So how much is that really?

One student decided to help illustrate this by creating an art installation, cordoning off a 27-ft x 27-ft x 27-ft cube in the student center with red ribbon.

Now imagine 24,000 of these cubes emanating from a college campus each year.   That helps show the magnitude of the challenge.

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Photo courtesy of Bowdoin College

It’s been easy for citizens of the developed, industrialized world to criticize China and India over their rapidly growing greenhouse gas emissions.  This was one of the major reasons why the Kyoto Protocol was never ratified in the United States.

As many have  pointed out, however, there are several flaws with this argument:

• The per-capita carbon emissions in China and India remain much lower (1/4 and 1/16, respectively) compared to the U.S..
• Perhaps more importantly, some of the carbon emission in these countries is caused by the production of export goods to fuel consumer demand in wealthy nations.  Thus, we are responsible for “shadow carbon emissions” that get attributed to developing nations.

Until today, there haven’t been very good estimates of these kinds of shadow emissions.

In the Early Edition of the Proceedings of the National Academy of Sciences, Steven Davies and Ken Caldeira examine how much CO₂ is embodied in the import and export of goods.¹

Their results are interesting (excerpts below—If you can get a copy of the article, check out figures 1 and 2; they are terrific visuals for this information.  Alas, copyrights don’t allow me to post them):

• Approximately 6.2 gigatonnes (Gt) of CO₂, 23% of all CO₂ emissions from fossil-fuel burning, were emitted during the production of goods that were ultimately consumed in a different country.
• Emissions imported to the United States exceed those of any other country or region, primarily embodied in machinery (91 Mt), electronics (77 Mt), motor vehicles and parts (75 Mt), chemical, rubber, and plastic products (52 Mt), unclassified manufactured products (52 Mt), wearing apparel (42 Mt), and intermediate goods (654 Mt).
• These imports are offset by considerable US exports of transport services (49 Mt CO₂), machinery (42 Mt), electronics (26 Mt), chemical, rubber, and plastics products (25 Mt), motor vehicles (22 Mt), and intermediate goods (263 Mt).
• [G]oods imported to Western Europe and Japan embody much more CO2 per US$ than do their exports, reflecting the import of energy-intensive products from elsewhere.
• The carbon intensity of imports to China, Russia, India, and the Middle East is consistently far less than that of their exports.
• China is by far the largest net exporter of emissions, followed by Russia, the Middle East, South Africa, Ukraine, and India and, to a lesser extent, Southeast Asia, Eastern Europe, and areas of South America.
• The primary net importers of emissions are the United States, Japan, the United Kingdom, Germany, France, and Italy. Although the overall mass of emissions is much less, the other countries of Western Europe are all net importers, as are New Zealand, Mexico, Singapore, and many areas of Africa and South America. Similarly, Canada, Australia, Indonesia, the Czech Republic, and Egypt are among the countries whose net exports of emissions are small.
• On a per-capita basis, net imports of emissions to the United States, Japan, and countries in Western Europe are disproportionately large, with each individual consumer associated with 2.4–10.3 tons of CO₂ emitted elsewhere.

Their conclusion:

Consumption-based accounting reveals that substantial CO₂ emissions are traded internationally and therefore not included in traditional production-based national emissions inventories. The net effect of trade is the export of emissions from China and other emerging markets to consumers in the United States, Japan, and Western Europe. In the large economies of Western Europe, net imported emissions are 20–50% of consumption emissions; the net imported emissions fall to 17.8% and 10.8% in Japan and the United States, respectively. In contrast, net exports represent 22.5% of emissions produced in China. Thus, to the extent that constraints on emissions in developing countries are the major impediment to effective international climate policy, allocating responsibility for some portion of these emissions to final consumers elsewhere may represent an opportunity for compromise.

¹Steven J. Davis and Ken Caldeira (2010). Consumption-based accounting of CO2 emissions PNAS : 10.1073/pnas.0906974107

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Photo Credit: http://www.flickr.com/photos/deks/ / CC BY-NC 2.0