IPCC Hones Its Language on Climate Change

The Athabasca Glacier, a part of the Columbia Icefields in Alberta, Canada, is receding on an average of 16 feet per year.
The Athabasca Glacier, a part of the Columbia Icefields in the Rocky Mountains of Alberta, Canada, has receded 0.93 miles (1.5 km) over the last 125 years.

Yesterday the Intergovernmental Panel on Climate Change (IPCC) released its latest Synthesis Report (SYR5) – a summary of the IPCC’s Fifth Assessment Report (AR5) on the state of knowledge on climate change. The big news with the SYR5’s release is the change in language used within the report – words like “unequivocable” and “clear” now replace the earlier usage of “probable” and “likely” when describing global warming and the role that human activity has played in the temperature increase. Text from the SYR5 underscores this major language shift:

 “Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, and sea level has risen.”

…and

“Human influence on the climate system is clear, and recent anthropogenic emissions of greenhouse gases are the highest in history.”

The SYR5 summarizes IPCC’s three other major reports on various facets of climate change that were released in 2013-2014. These reports are all available from the IPCC website:

  • Climate Change 2013 – The Physical Science Basis;
  • Climate Change 2014 – Impacts, Adaptations, and Vulnerability; and
  • Climate Change 2014 – Mitigation of Climate Change.

The Carbon Brief 11/2/2014 blog gives a listing and good, brief descriptions of what else is noteworthy in the SYR5. Here’s a quick recap on their list:

  • Global warming continues unabated
  • Human influence on warming is clear
  • Ocean acidification, sea level rise, glacial ice decline
  • IPCC’s new carbon budget
  • Consequences of inaction – climate change impacts
  • Low carbon transition – costs and savngs

Greenland’s Fastest Glacier Now Flowing At Record Speeds

Jakobshavn Isbræ, Greenland’s fastest flowing glacier, has been moving even faster over the past several years. The Jakobshavn Glacier, or Jakobshavn Isbræ, is located on the west coast of Greenland and drains a major part of the Greenland ice sheet into a deep ocean fjord. Accordingly, the Jakobshavn Glacier could add significantly to sea level rise.

Recorded speeds of glacial flow during the summer of 2012 topped out at more than 17 kilometers per year, or over 46 meters per day. In fact, the transient summer speeds observed for 2012 probably represent the fastest observed speeds for any outlet glacier or ice stream in Greenland or Antarctica. In a paper published recently in The Cryosphere, Joughin and others, note that:

We have extended the record of flow speed on Jakobshavn Isbræ through the summer of 2013. These new data reveal large seasonal speedups, 30 to 50% greater than previous summers. At a point a few kilometres inland from the terminus, the mean annual speed for 2012 is nearly three times as great as that in the mid-1990s, while the peak summer speeds are more than a factor of four greater. These speeds were achieved as the glacier terminus appears to have retreated to the bottom of an over-deepened basin with a depth of 1300m below sea level. The terminus is likely to reach the deepest section of the trough within a few decades, after which it could rapidly retreat to the shallower regions 50 km farther upstream, potentially by the end of this century.

The warming trend in the Arctic correlates with Greenland’s glaciers thinning and retreating progressively inland. The rapid retreat of the Jakobshavn Isbræ, however, is due not only to the warming trend, but to a number of feedbacks. The primary control on the glacial flow now is the physical location of the glacier’s calving front. The calving front is currently located in a deep area of its outlet fiord, an area where the underlying rock bed is about 1300 meters below sea level. As the glacier loses ice in this area – basically the ice in front that is holding back the flow – the flow speeds up.

The contribution to sea level rise from the Jakobshavn Isbræ may be significant. One of the study’s authors, Ian Joughlin, is quoted in Science Daily, 2/3/2014, as saying:

We know that from 2000 to 2010 this glacier alone increased sea level by about 1 mm. With the additional speed it likely will contribute a bit more than this over the next decade.

So what should we expect for the Jakobshavn Isbræ’s future? Joughlin and others summarized this by:

Thus, the potential for large losses from Greenland is likely to be determined by the depth and inland extent of the troughs through which its outlet glaciers drain. These features are only beginning to be well resolved by international efforts such as NASA’s Operation IceBridge. The relatively sparse data collected thus far indicate that, with its great depths and inland extent, Jakobshavn’s Isbræ is somewhat unique (Bamber et al., 2013), suggesting that it may be difficult for the majority of Greenland’s outlet glaciers to produce or to sustain such large increases in ice discharge.

Of interest may be an earlier Geopostings on “Chasing Ice” that showed a 2012 huge calving event from the Jakobshavn Isbræ.

Rising Seas and Carbon Footprint Visualizations

National Geographic "Rising Seas" map of projected North American shoreline change from ice melt. Map from: http://tiny.cc/xc0z9w
National Geographic “Rising Seas” map of projected North American shoreline change from ice melt. Map from: http://tiny.cc/xc0z9w

New sets of interactive maps help to visualize both the impact of rising seas on the world’s coastlines and U.S household carbon footprints.National Geographic has posted a set of world-wide interactive maps that show new coastal outlines resulting from the premise of all ice melting and thus raising sea level approximately 216 feet. As noted by the authors:

There are more than five million cubic miles of ice on Earth, and some scientists say it would take more than 5,000 years to melt it all. If we continue adding carbon to the atmosphere, we’ll very likely create an ice-free planet, with an average temperature of perhaps 80 degrees Fahrenheit instead of the current 58.

Continuing on the topic of adding carbon to the atmosphere, University of Berkeley researchers, Christopher Jones and Daniel Kammen, looked at the spatial distribution of U.S. household carbon footprints. The researchers first point out the obvious in that carbon footprints in densely populated areas are typically low because of smaller residences, shorter commutes, and the availability of mass transit. Here’s the catch though – the suburbs have an unusually large carbon footprint. In fact the footprint is so large that it negates the “green” urban core. As Jones and Kammen summarize:

As a policy measure to reduce GHG emissions, increasing population density appears to have severe limitations and unexpected trade-offs. In suburbs, we find more population- dense suburbs actually have noticeably higher HCF, largely because of income effects. Population density does correlate with lower HCF when controlling for income and household size; however, in practice population density measures may have little control over income of residents. Increasing rents would also likely further contribute to pressures to suburbanize the suburbs, leading to a possible net increase in emissions. As a policy measure for urban cores, any such strategy should consider the larger impact on surrounding areas, not just the residents of population dense communities themselves. The relationship is also log−linear, with a 10-fold increase in population density yielding only a 25% decrease in HCF. Generally, we find no evidence for net GHG benefits of population density in urban cores or suburbs when considering effects on entire metropolitan areas.

U.S. Average Annual Household Carbon Footprint by Household. "Source: UC Berkeley CoolClimate Network, Average Annual Household Carbon Footprint (2013)"
U.S. Average Annual Household Carbon Footprint by Household. “Source: UC Berkeley CoolClimate Network, Average Annual Household Carbon Footprint (2013)”

 

Climate Change Impact on Earth Surface Systems

As Congress continues to stonewall on climate change legislation, I think that a recent article published in the Perspectives section of Nature Climate Change, The impacts of climate change on terrestrial Earth surface systems, is worth contemplating. The authors, Jasper Knight and Stephan Harrison, argue that “… at present, governments’ attempts to limit greenhouse-gas emissions through carbon cap-and-trade schemes and to promote renewable and sustainable energy sources are probably too late to arrest the inevitable trend of global warming. Instead, there are increasingly persuasive arguments that government and institutional focus should be on developing adaption policies that address and help mitigate against the negative outcomes of global warming, rather than carbon trading and cataloguing greenhouse-gas emissions”.

Don’t think that the authors suggest for us to just walk away from the greenhouse-gas emission and global warming problem, though. What they are advocating is a more inclusive strategy for dealing with global warming, one that includes understanding and managing the impacts of climate change on the dynamics of Earth surface systems – systems that include glaciers, rivers, mountains and coasts. These systems supply resources such as soil and water, and as such are critical components to life on earth. And, as we just witnessed with Superstorm Sandy, some of these systems, such as coastal and river systems, are vital in alleviating the impact of catastrophic weather events.

The major problem with immediately incorporating earth surface system data into a global warming management response is that earth surface systems operate on a much longer time scale than elements of the biosphere. To mitigate the time dilemma, there is potential in looking at earth surface system responses to past climatic events. Knight and Harrison note that, “…for instance, climate cooling during the Little Ice Age in Europe (~ad 1550–1850) had significant impacts on the sediment yields of mountain, fluvial and slope systems, particularly in marginal regions already predis­posed to be climatically sensitive to changes in temperature and pre­cipitation patterns, including their seasonality”.

In any event, currently, most Earth surface systems are not regularly monitored regarding climate change. This is a huge policy omission, both nationally and internationally, because Earth surface system dynamics are a major part of the landscape response to climate change, and these systems function on multinational spatial scales that play into sustainable resource management. It is going to take a large-scale effort by scientists, governments, and most importantly, citizens to make sure that the response to global warming includes understanding and managing the impacts of climate change on the dynamics of Earth surface systems. It’s long past time to get to work.

Largest Ice Calving Event Caught on Video

As part of the filming for the documentary,Chasing Ice, two filmmakers caught a massive calving event of a Greenland glacier (see the accompanying YouTube video, via The Guardian, inserted below). One of the filmmakers, James Balog, said the event is like seeing “Manhattan breaking apart in front of your eyes”. Chasing Ice chronicles climate change’s impact on Arctic glaciers. Balog began his multiyear time-lapse photographic expedition in 2005. With the help of other adventurers, and on assignment for National Geographic, Balog set up cameras across the Arctic in hopes of documenting the changing glaciers. The result of this work clearly records the disappearance of Arctic glaciers and a transformation of our planet.

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The only place that I’ve found Chasing Ice currently playing in Montana is at the Wilma Theater in Missoula. It is scheduled to be at the Wilma at least until next Wednesday, 12/19. The Chasing Ice website does have a form available whereby a request can be made to bring the film to more local theaters. Here’s the link: http://www.chasingice.com/see-the-film/bring-it-to-my-local-theater/ . Let’s bring it to more places in Montana. Everyone should see this!

Polar Ice Melting Fast

A new study published in Science on 11/30/2012 shows that the Antarctic and Greenland ice sheets are losing more than three times as much ice each year as they were in the 1990s. The melting of ice, two thirds of which has occurred in Greenland, has raised sea levels by 11.1 millimeters since 1992.

ice melt
Source: ESA/NASA/Planetary Visions
Based on the Shepherd et.al. Science study, this image of Antarctica has a superimposed chart of changes in global sea level due to ice sheet melting since 1992. The background image shows thickening (blue) and thinning (red) of Antarctica’s ice sheets over the same period.

The study is the combined work of 47 researchers from 26 laboratories and was  supported by the European Space Agency and the National Aeronautics and Space Administration. As summarized in the abstract of the Science publication, “We combined an ensemble of satellite altimetry, interferometry, and gravimetry data sets using common geographical regions, time intervals, and models of surface mass balance and glacial isostatic adjustment to estimate the mass balance of Earth’s polar ice sheets. We find that there is good agreement between different satellite methods—especially in Greenland and West Antarctica—and that combining satellite data sets leads to greater certainty. Between 1992 and 2011, the ice sheets of Greenland, East Antarctica, West Antarctica, and the Antarctic Peninsula changed in mass by –142 ± 49, +14 ± 43, –65 ± 26, and –20 ± 14 gigatonnes year−1, respectively. Since 1992, the polar ice sheets have contributed, on average, 0.59 ± 0.20 millimeter year−1 to the rate of global sea-level rise.”

The research was undertaken as part of the Ice Sheet Mass Balance Inter-comparison Exercise (IMBIE). Read more on the study: Science – A Reconciled Estimate of Ice-Sheet Mass Balance