Ocean Data Support Global Warming Projections
By J.R. Pegg
WASHINGTON, DC, April 29, 2005 (ENS) – A new study of ocean temperatures provides further evidence that human activities are warming the planet, scientists said Thursday. The Earth is absorbing more energy from the Sun than it is emitting back into space, according to the new study, and the magnitude of imbalance cannot be explained by natural variability.
Lead author James Hansen, director of NASA’s Goddard Institute for Space Studies, called the research the "smoking gun" that should put to rest any lingering doubts about humanity’s role in global warming.
The new study finds that the Earth's current energy imbalance is large by historic standards - for every square meter of surface area, the plant is absorbing about one watt of energy from the Sun more than it is radiating back out into space.
These pollutants, in particular carbon dioxide, methane and particulate matter, block the Earth's radiant heat from escaping into space, increasing absorption of sunlight and trapping heat within the atmosphere.
There is little doubt the planet is warming - the global average temperature increased about one degree Fahrenheit over the past century.
The study shows that "our estimates of the human-made and natural climate forcing agents are about right, and they are driving the Earth toward a warmer climate," Hansen said.
"There can no longer be substantial doubt that human-made gases are the cause of most observed warming," he said.
The findings of the 15 member research team were published Thursday by the journal "Science."
Rather than showing an immediate temperature increase, the ocean traps the heat within its depths – a phenomenon known as "thermal inertia."
This means there is an additional global warming of about one degree Fahrenheit (0.6 Celsius) "in the pipeline" that will show in overall ambient temperature this century, according to the research team, even if humanity stopped emitting new greenhouse gases immediately.
Humanity primarily produces greenhouse gases by the combustion of fossil fuels, such as coal and oil, and all indications are that emissions will continue to rise for the foreseeable future.
Developing nations, in particular China and India, are predicted to boost their emissions as their economies continue to grow, and the United States, which is responsible for more than a quarter of humanity’s greenhouse gas emissions, has balked at mandatory reductions.
Such increases could spin the climate system "out of our control," the researchers said, in particular as sea levels rise from melting ice sheets in Greenland and Antarctica.
Sea levels rose some 1.26 inches (3.2 centimeters) in the past decade, Hansen said, an increase twice the rate of the last century.
The study led by Hansen on the Earth’s energy imbalance comes on the heels of new research from the British Antarctic Survey (BAS) that finds more than 200 coastal glaciers in Antarctica are in retreat because of higher temperatures.
The BAS study, published last week in "Science," reports that 87 percent of the 244 marine glaciers that drain inland ice on the Antarctic peninsula have retreated in the last 50 years and that average retreat rates have accelerated in recent years.