It is still unusual how some people wonder if climate change is true. Today we have new evidence showing that climate change is very real and caused by humanity.
Our planet is continually trying to balance the energy that comes from the Sun and that released into space. First, this energy enters through sunlight; Part of this energy is reflected on the surface of the Earth and part returns to space; the rest is absorbed, warms the planet and is emitted as thermal radiation energy as when asphalt heats up in summer and emits heat during a sunny day.
However, new data provided by NASA show that, since the industrial revolution, humanity has unbalanced this energy budget, adding greenhouse gases that trap more radiation. These greenhouse gases lead to what is known as “radiative forcing”, since adding more components that absorb radiation or eliminating those that reflect it, such as aerosols, alter this energy balance that causes the Earth to absorb more energy than the which should escape into space (further heating the surface).
The researchers, publishing their findings in the journal Geophysical Research Letters, have established the evidence by studying greenhouse gas concentrations and surface temperature changes over the past 150 years, but not directly. These are the first direct observations of increasing global radiative forcing. It is the way in which human activities are affecting the climate.
“This is the first calculation of the Earth’s total radiative forcing using global observations, taking into account the effects of aerosols and greenhouse gases,” says Ryan Kramer of NASA’s Goddard Space Flight Center and the University of Maryland. . “It is direct proof that human activities are causing changes in the Earth’s energy budget.”
To achieve these results, NASA scientists used the Clouds and the Earth’s Radiant Energy System (CERES) project that has flown continuously on satellites since 1997. Each of these instruments accurately measures how much energy is entering the Earth’s system and how much comes out. “But it doesn’t tell us what factors are causing changes in the energy balance ,” Kramer added.
How much of this energy imbalance has been caused by humans?
To find out, they looked at how much of that imbalance was due to fluctuations in factors that often occur naturally. Clouds, surface brightness, and water vapor are some examples. The Atmospheric Infrared Sounder instrument on NASA’s Aqua satellite measures the water vapor in our atmosphere, which absorbs heat, so depending on the amount of moisture in the atmosphere, the amount of energy leaving the Earth will be different. Finally, they demonstrated with a new computer algorithm that radiative forcing has increased by 0.5 watts per square meter from 2003 to 2018. This is mainly due to increases in greenhouse gas emissions.
Experts share that “this will allow us to make more confident projections about how the climate will change in the future.”
Referencia: Ryan J. Kramer et al. Observational evidence of increasing global radiative forcing, Geophysical Research Letters (2021). DOI: 10.1029/2020GL091585
