World carbon emissions will essentially have to come to a halt by midcentury to avoid severe disruption of the earth's climate system, warn the 47 authors of the Worldwatch Institute's book, State of the World 2009: Into a Warming World.
Released Tuesday, the Washington, D.C., sustainability research group's 26th annual State of the World report says that the coming year will be crucial for the earth's climate. In December, world leaders will gather in Copenhagen, Denmark, to hammer out a successor to the Kyoto Protocol, which sought to curb greenhouse-gas emissions to prevent the earth from warming more than 3.6 degrees Fahrenheit above preindustrial levels. Scientists say the planet's average temperature has gone up 1.4 degrees F. since the mid 18th century.
But this threshold is probably too high, argues a chapter by climate scientist W.L. Hare. A 3.6 degree F. rise would probably lead to mass extinctions, famine, water shortages, and coastal flooding, writes Mr. Hare, an environmental scientist with the Potsdam Institute for Climate Impact Research and a lead author of the United Nation's climate panel's seminal 2007 report on global warming. Hare, who says that uncertainties about climate sensitivity make it impossible to define an unambiguously safe warming threshold, urges that we do everything we can to avoid a warming of more than 0.4 degrees above present levels.
To achieve this, greenhouse gas emissions should peak no later than 2020, drop to 85 percent below 1990 levels by 2050, and then "go negative," with more C02 being absorbed than emitted, soon after that.
The greater burden of these reductions should fall on wealthy, industrialized countries, says Hare. These countries should cut their emissions by as much as 95 percent, to allow developing countries to grow their economies and develop renewable energy infrastructures.
This is a very tall order, and more than what's called for by most policymakers. For instance, President-elect Barack Obama's plan is to cut US emissions by 80 percent below present levels by 2050, with no mention of a 2020 peak. US emissions are about 15 percent higher than they were in 1990.
Worldwatch recommends drastic cuts, but they should not be seen as discouraging, say book's authors. A chapter on renewable-energy opportunities by Worldwatch researcher Janet Sawin and Tufts environmental studies professor William Moomaw notes that a century ago, few would have imagined that widespread household electrification and automobile ownership were just four decades away. In 2009, they write:
[Who] can imagine how the mid-21st century global economy will be transformed by more-efficient use of energy and cost-effective renewable energy sources, and how much they will limit the release of greenhouse gases into the atmosphere? We have a once-in-a-century opportunity to make a transformation from an unsustainable economy fueled by poorly distributed fossil fuels to an enduring and secure economy that runs on renewable energy that lasts forever.
The book, which contains a foreword by R.K. Pachauri, the head of the UN's climate panel, aims for comprehensiveness. There are chapters exploring the threats that climate change poses to national security, jobs, human health, biodiversity, and island nations, interspersed with chapters on possible solutions, including electric vehicles, carbon capture and storage technologies, market incentives, and even "geoengineering" the climate by seeding the atmosphere with heat-reflecting sulfur dust. There's even a chapter by psychologist Tim Kasser on those who use the environmental crisis as an opportunity to try to shift their values away from materialism (an idea this blog explored last June).