Rising Seas and Carbon Footprint Visualizations

National Geographic

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 and are always in serious need of carbon management. 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.

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

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