LOS ANGELES - NASA has found direct evidence that shows how humans are impacting and causing a change in Earth’s climate.
"Our study is the first time we’ve been able to track how humans are directly changing Earth’s energy balance on the global scale over time with observations," Ryan Kramer, a co-author of the study, told FOX Television Stations.
Scientists have long known that climate change is a response to energy imbalances in the climate system. For example, rising greenhouse gases directly cause an initial imbalance in the planetary radiation budget and surface temperatures increase in response as the climate attempts to restore balance.
This forcing and its subsequent feedbacks dictate the amount of warming in the atmosphere.
The study, which is described as a first of its kind, calculated driving forces and found they increased between 2003 and 2018, accounting for nearly all of the long‐term growth in the total top‐of‐atmosphere radiation imbalance during this period.
"We confirm that rising greenhouse gas concentrations account for most of the increases in the radiative forcing, along with reductions in reflective aerosols. This serves as direct evidence that anthropogenic activity has affected Earth’s energy budget in the recent past," NASA wrote.
While scientists have long known that there is a causation between humans and Earth’s warming, the study is the first by NASA that directly links humans to recent climate change.
"Our results show that human actions are directly changing the Earth’s energy balance. It’s confirmation from observations that human activity is leading to climate change. While we’ve known this for decades and there are countless other lines of evidence, our finding is based on direct, modern-day global observations while the other sources of evidence often require at least a little bit of interpretation using climate model simulations," Kramer continued.
NASA calculated and quantified the individual forcings from specialized satellite measurements to determine how much of each component cooled or warmed the atmosphere. The scientists found that the forces by computer models for decades matched the changes they calculated in the observations.
"By bringing in additional types of satellite measurements, we were able to first diagnose the energy changes caused by processes that can be either human-caused or naturally occurring, such as changes in clouds, which reflect and absorb energy, or changes in the amount of moisture in the air. We then diagnosed the portion of the energy change left over, after subtracting these components from the total. This is the energy change specifically caused by emissions of heat trapping greenhouse gases or reductions in aerosols – energy reflecting particles that often come from pollution. These human-induced energy changes are known as the radiative forcing of the Earth. Our study is the first to diagnose it on the global scale with observations," Kramer explained.
Kramer said the scientific result of this study is not surprising but is a testament to the progress that the science and engineering fields have made over the decades.