First-of-its-kind detection of reduced human carbon dioxide emissions

For the first time, researchers have spotted short-term regional fluctuations in atmospheric carbon dioxide due to emissions from human activities.

The scientists performed a first-of-its-kind detection of human CO 2 emissions changes using a combination of NASA satellites and atmospheric modeling. The new study uses data from NASA to measure drops in CO 2 emissions during the COVID-19 pandemic from space. With daily and monthly data products now available to the public, this opens new possibilities for tracking the collective effects of human activities on CO 2 concentrations in near real-time.

Global CO 2 levels dropped slightly in 2020 after previous studies investigated the effects of lockdowns early in the Pandemic. The team was able to narrow down which monthly changes were due to human activity and which were due to natural causes by combining OCO-2's high-resolution data with modeling and data analysis tools from NASA. The previous estimates were based on economic and human activity data.

In the Northern Hemisphere, human-generated growth in CO 2 concentrations dropped from February through May 2020 and rebounded during the summer, consistent with a global emissions decrease of 3% to 13% for the year.

The team said that the results represent a leap forward for researchers studying regional effects of climate change. The method allows detection of changes in atmospheric CO 2 within a month or two after they happen, providing fast, actionable information about how human and natural emissions are evolving.

Figuring out subtle changes in Earth's atmosphere.

Carbon dioxide (CO 2 ) is a greenhouse gas present in the atmosphere and its concentration changes due to natural processes. For the first time in human history, the concentration of CO 2 in the atmosphere has increased since the Industrial Revolution.

The amount of greenhouse gases and pollutants released into the atmosphere dropped steeply when governments asked citizens to stay home early in the COVID-19 epidemic. A research meteorologist at NASA's Global Modeling and Assimilation Office said that a "steep drop" in CO 2 needs to be put in context. This gas can last in the atmosphere for up to a century after it is released, which is why short-term changes could get lost in the overall global carbon cycle. The total CO 2 picture for the year includes the early 2020 lockdowns.

The challenge is to understand what all the different influences are.

Satellite technology has made it possible to measure these kinds of changes. NASA's OCO-2 satellite has high-precision spectrometers designed to pick up even smaller fluctuations in CO 2, and combined with the comprehensive GEOS Earth system model, were a perfect fit to spot the Pandemic-related changes.

The OCO-2 wasn't designed for monitoring emissions, but it is designed to see even smaller signals than what we saw with COVID. The OCO-2 mission research goal was to track how human emissions shifted in response to climate policies, which are expected to produce small, gradual changes in CO 2

The team compared the measured changes in atmospheric CO 2 with the estimates of emissions due to lockdowns. The agreement between emissions models and atmospheric CO 2 measurements provides strong evidence that the reductions were due to human activities.

Ott said that the study really is bringing everything together to attack an enormously difficult problem.

Taking a closer look at greenhouse gases.

Growth in CO 2 concentrations dropped in the Northern Hemisphere from February through May 2020 (corresponding to a global emissions decrease of 3% and 13%), which was agreed with computer simulations of how activity restrictions and natural influences should affect the atmosphere.

The signal was not as clear in the Southern Hemisphere because of the Indian Ocean Dipole. The IOD is a pattern of cooler-than-normal oceans in Southeast Asia and warmer-than-normal oceans in the eastern Indian Ocean. The IOD experienced an intense positive phase in the middle of the year, yielding a plentiful harvest season in sub-Saharan Africa and contributing to the record-setting Australian fire season. The team said that both events affected the carbon cycle and made detecting the signal of COVID lockdowns difficult.

One of the indicators in the COVID-19 Earth observing dashboard is powered by the data from the OCO-2. The dashboard compiles global data and indicators to track how COVID-related actions are affecting the environment.

The free download of the GEOS-OCO-2 assimilated product makes it accessible to researchers and students who want to investigate further.

Ott said that scientists could go to the dashboard and say, "I see something interesting in the CO 2 signal."

The team said that the new method could be used to help monitor the results of climate programs at the community or regional level.

Ott said that being able to monitor how our climate is changing is something that is really proud of.

More information: Brad Weir et al, Regional impacts of COVID-19 on carbon dioxide detected worldwide from space, Science Advances (2021). DOI: 10.1126/sciadv.abf9415 Journal information: Science Advances Citation: First-of-its-kind detection of reduced human carbon dioxide emissions (2022, April 1) retrieved 1 April 2022 from https://phys.org/news/2022-04-first-of-its-kind-human-carbon-dioxide-emissions.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.