Still a Lot to Learn about Climate Change

As the governor’s commission on climate change starts digging into the impact of Global Warming on Virginia — a particular concern is the expected three-foot rise of sea levels by the end of the century — it would do well to acknowledge the evolving state of climate science. Nearly every day brings some new discovery that refines our knowledge of the mechanics of climate change. The latest, as reported by National Public Radio, highlights “the mystery of Global Warming’s missing heat.”

While surface temperatures on the earth have been warming over the past four or five years, temperatures in the oceans have showed no warming — indeed, according to reports of some 3,000 robotic sensors scattered around the earth’s oceans, known as the Argo system, the waters might actually have cooled a bit. That’s relevant to Virginians for a couple of reasons: (a) the oceans hold significantly more of the earth’s surface heat than the atmosphere does, and (b) the warming of the ocean, which slightly expands its mass, is expected to be a driving force of rising sea levels.

For Virginians, rising sea levels are the cutting edge of climate change. Other than New Orleans, Hampton Roads is the lowest-lying large metropolitan area in the country, and it is exceptionally vulnerable to rising sea levels. Also, the Chesapeake Bay ecosystem is vulnerable to salification as ocean water displaces fresh water in the estuary.

The new Argo system measurements appear to be inconsistent with the predictions of climate change models that temperatures and are destined to rise. Scientists are baffled. Perhaps it’s just a measurement error: The ocean’s heat might be circulating to deeper levels not tracked by the sensors. Alternatively, the earth’s natural thermostats may be allowing more heat to be released into space than expected. Or, concedes Kevin Trenberth at the National Center for Atmospheric Research, there may be a dynamic at work that science has not yet identified.

Here’s another curve ball. In theory, because ocean water temperature should account for about half of rising/falling sea levels, sea levels should not have been rising over the past few years. But they have continued to rise — about 1/2 inch over four years. Scientists guess that the melting of Greenland and Antarctic icecaps may account for the rise. There are so many variables in the climate, however, that nobody knows for sure.

One more thing for Virginia’s climate change commission to think about: If sea levels are rising 1/2 inch over four years, that implies a rate of one inch per eight years. If the rate stays constant for the rest of the century, that implies that sea levels will be 11.5 inches higher — less than one foot — by the year 2100. As I recall, the commission is operating on an assumption that sea levels will rise three feet over that period.

The fact is, nobody knows what sea levels will do, and anyone who speaks with certainty is blowing hot air. What we can say with some confidence is that there is a significant risk, based on our current knowledge, that sea levels will rise. We need to take those risks into account as we plan for Virginia’s future, and we need to continually update and modify our assessment of those risks to reflect the best scientific knowledge as we go forward.

(Image credit: From Vanity Fair, a photo of what Manhattan might look like if sea levels continue to rise, “Notes of Intelligence” blog.)

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  1. Anonymous Avatar

    Love the picture. It lends a certain Venetian charm to the once-dingy (sp?) Big Apple. Of course, they’d have to renumber the floors in a lot of buildings, but the idea of going from meeting to meeting in the company of a singing Gondolier cheers me immensely.

    NoVA Scout

  2. Larry Gross Avatar
    Larry Gross

    NYC – perhaps more than many other cities is truly an “underground” city as most of us were reminded on 9-11.

    virtually all of the utilities as well as subways, etc are at or below the basement levels of buildings….

    Right now.. among those trying to figure out how “real” this particular aspect of global warming might be – are the insurance companies.

    We can all continue to argue about it.. but when the insurance companies “speak” .. especially if they start saying “no way can we insure” that.. beach house… low-lying subdivisions… buildings at or near sea level… THAT’s when we can stop arguing about what the impacts might or might not be.

    I’ve always wondered if multi-story beach hotels were built differently than downtown office buildings in terms of what floor their utilities are on.

    anyone know?

    perhaps the other tell-tale indicator of how seriously insurance companies believe in the impacts is when they say..

    “sure we’ll insure your building… “… “if you build it like the first 2 floors will flood”.


  3. Anonymous Avatar

    Global Warming and Climate Change:
    The Skeptics Continue to Gain Strength
    It is amazing/revealing that so many scientists who once accepted the claims that human discharge of C02 into the atmosphere is causing global warming have changed their minds. From the Adam Smith Blog,

    A new ‘Manhattan Declaration on Climate Change’ was initiated stating “that carbon dioxide (CO2) is not a pollutant but rather a necessity for all life.” Senator Inhofe’s register, put together by the USA Senate’s Environment and Public Works Committee, already contains more than 500 scientists who previously endorsed the IPCC views but have meanwhile changed their mind. The sceptics have reached a consensus on four key points:

    1) The Earth is currently well within natural climate variability. 2) Almost all climate fear is generated by unproven computer model predictions. 3) An abundance of peer-reviewed studies continue to debunk rising CO2 fears and, 4) “Consensus” has been manufactured for political, not scientific purposes.

    Contrary to expectations the media coverage was excellent – that’s the new momentum.
    And let me add that even if those who disagree with the skeptics are correct, it might be cheaper and more efficient to deal with the effects of global warming rather than try to stop it.

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