In climate science, Radiative Forcing or climate forcing, is defined as the difference of radiant energy received by the Earth, and energy radiated back to space.
A positive radiative forcing tends on average to warm the surface of the Earth, and negative forcing tends on average to cool the surface.
Between the start of the Industrial Era and roughly present time (~1750 – 2005) the values of Radiative Forcing for some of the main atmospheric agents, commonly referred to as greenhouse gases, are as follows:
Carbon Dioxide - from 1.49 to 1.83 W/m²
(average RF value of 1.66 W/m²).
Methane - from 0.43 to 0.53 W/m²
(average RF value of 0.48 W/m²).
Nitrous Oxide - from 0.14 to 0.18 W/m²
(average RF value of 0.16 W/m²).
Halocarbon gases - from 0.31 to 0.37 W/m²
(average RF value of 0.34 W/m²)
The above data clearly show that there has been a noticeable increase in the overall Radiative Forcing value, due to the effects of the increase in the emission of greenhouse gases, in recent times, indicating a warming effect on the earth.
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The Union of Concerned Scientists puts rigorous, independent science to work to solve our planet's most pressing problems. Joining with citizens across the country, they combine technical analysis and effective advocacy to create innovative, practical solutions for a healthy, safe, and sustainable future.
UCS members are people from all walks of life: parents and businesspeople, biologists and physicists, teachers and students. Their members understand that scientific analysis—not political calculations or corporate hype—should guide our efforts to secure responsible changes in government policy, corporate practices, and consumer choices.
Here is their view on Global Warming:
The planet's temperature is rising. The trend is clear and unmistakable.
Every one of the past 37 years has been warmer than the 20th century average. The 12 warmest years on record have all occurred since 1998. 2012 was the hottest year ever recorded for the contiguous United States.
Globally, the average surface temperature has increased more than one degree Fahrenheit since the late 1800s. Most of that increase has occurred over just the past three decades.
We are overloading our atmosphere with carbon dioxide, which traps heat and steadily drives up the planet’s temperature. Where does all this carbon come from? The fossil fuels we burn for energy — coal, natural gas, and oil — plus the loss of forests due to deforestation, especially in the tropics.
Within the scientific community, there is no debate: An overwhelming majority of climate scientists agree that global warming is happening and that human activity is the primary cause.
This broad consensus — and the extensive scientific evidence that supports it — is often downplayed or distorted by a small but vocal minority of special interests that have a vested interest in delaying action on climate change.
Why has it been so difficult to achieve meaningful solutions to global warming? Media pundits, partisan think tanks, and special interest groups funded by fossil fuel and related industries raise doubts about the truth of global warming.
These contrarians downplay and distort the evidence of climate change, demand policies that allow industries to continue polluting, and attempt to undercut existing pollution standards.
This barrage of misinformation misleads and confuses the public about the growing consequences of global warming— and makes it more difficult to implement the solutions we need to effectively reduce the man-made emissions that cause global warming.
Together with its members and supporters, UCS actively fights misrepresentations of climate science and provides sound, science-based evidence to set the record straight, including resources to help communicate the real facts about global warming.
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