Is infrared energy melting the Arctic?
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It's been overlooked for decades, but now scientists believe infrared energy could turn out to be a major contributor to warming in the Arctic region.
Infrared is invisible to human eyes but accounts for about half the energy emitted by Earth's surface. This process balances out incoming solar energy.
However, researchers hadn't previously thought to consider the long-wavelength region of the electromagnetic spectrum. Now, they believe its inclusion could change existing climate models.
This simulation shows averaged radiative surface temperature changes during the 2030s after far-infrared surface energy was taken into account. The right colour bar depicts temperature change in Kelvin
Earth's surface is thought to radiate the equivalent of 17 per cent of incoming solar energy as thermal infrared.
Despite its importance in the planet's energy budget, it's difficult to measure a surface's effectiveness in emitting far-infrared energy.
As a result, its influence on the planet's climate is not well represented in climate models, which assume that all surfaces are 100 per cent efficient in emitting far-infrared energy.
That's not the case. The scientists found that open oceans are much less efficient than sea ice when it comes to emitting in the far-infrared region of the spectrum.
It's been overlooked for decades, but now scientists believe infrared energy could turn out to be a major contributor to warming in the Arctic region (pictured)
This means that the Arctic Ocean traps much of the energy in far-infrared radiation - a previously unknown phenomenon that is likely contributing to the warming of the polar climate.
'Far-infrared surface emissivity is an unexplored topic, but it deserves more attention,' said Daniel Feldman, a scientist in Berkeley Lab's Earth Sciences Division.
'Our research found that non-frozen surfaces are poor emitters compared to frozen surfaces. This discrepancy has a much bigger impact on the polar climate than today's models indicate.
Professor Feldman's simulations revealed that far-infrared surface emissions have the biggest impact on the climates of arid high-latitude and high-altitude regions.
In the Arctic, the simulations found that open oceans hold more far-infrared energy than sea ice, resulting in warmer oceans, melting sea ice, and a 2°C increase in the polar climate after only a 25-year run.
This could help explain why polar warming is most pronounced during the three-month winter when there is no sun.
It also complements a process in which darker oceans absorb more solar energy than sea ice.
'The Earth continues to emit energy in the far infrared during the polar winter,' Professor Feldman said.
Arctic sea ice hit its annual minimum on 17 September 2014. The red line in this image shows the 1981-2010 average minimum extent. Scientists believe the latest study will require existing climate models to be changed
'And because ocean surfaces trap this energy, the system is warmer throughout the year as opposed to only when the sun is out.'
The simulations revealed a similar warming effect on the Tibetan plateau, where there was five per cent less snowpack after a 25-year run.
This means more non-frozen surface area to trap far-infrared energy, which further contributes to warming in the region.
'We found that in very arid areas, the extent to which the surface emits far-infrared energy really matters,' said Professor Feldman.
'It controls the thermal energy budget for the entire region, so we need to measure and model it better.'
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