Space station precisely identifies main emitters of greenhouse gases on Earth

Since the Industrial Revolution in the 19th century^I century, humanity gradually began to manufacture products on a large scale, leading to ever-increasing energy needs. The first is produced primarily through combustion CoalCoal (for example we can think of the steam engine), then the energy production sectors expanded to include all fossil fuels, such as oil or natural gasnatural gas, ces fossil fuelfossil fuel Come from the slow decomposition of organic matter (consisting, among other things, of carbon) of living beings (plants). bacteriabacteria, animals…) in the depths of the soil, over several hundred million years. Although these energy sources provide satisfactory performance, the use of fossil fuels today represents a major disadvantage: the production of fossil fuels emits green house gasgreen house gas (like water, h₂of carbon dioxidecarbon dioxideCO₂or methane, CH₄), which persists in the bass AtmosphereAtmosphere a part of HeatHeat Is emitted towards space and heats it.

greenhouse gas problem

Without these greenhouse gases, climateclimate Terrestrial would be very inhospitable (the temperature on Earth’s surface would be around -18 degrees Celsius). On the other hand, an excess of atmospheric greenhouse gases makes the atmosphere excessively warm. This is the same problem humanity currently faces: since the Industrial Revolution, the average temperature at the Earth’s surface has already increased by 1.5°C, causing broadcastbroadcast Anthropogenic Greenhouse Gases. This trend is still increasing, which is having a dramatic impact on our environment and our climate (Wave’sWave’s heat, rising water, drydry at FloodsFloods), even our lives.

An explanation of the effect of greenhouse gases on temperatures at the Earth’s surface, taken from a webdoc in the words of climatologists. © CEA

The two main greenhouse gases of anthropogenic origin, that is, emitted by human activities, are carbon dioxide (CO)₂) and methane (CH₄), emitted for example from the combustion of coal or the extraction and use of natural gas. Although scientists are well aware of their main types of emission sources (power plants, refineries, etc.), it is difficult to accurately identify the sources of greenhouse gas emissions. Carbon dioxide and methane emissions are actually a significant source of uncertainty in the assessment billon carbonbillon carbon Global, especially when emissions originate at small spatial scales (typically less than a kilometer). These uncertainties vary depending on the country (up to a few percent for most). transparenttransparentup to several tens of percent for countries that are more cautious about their emissions, such as China).

To more accurately calculate the global carbon footprint, scientists have been trying to trace carbon emissions from space for several decades. Tropomy satellite (troposphere monitoring equipment) or OCO (Orbiting Carbon ObservatoryOrbiting Carbon Observatory), for example, had already been launched with this purpose; But scientists faced either ResolutionResolution The spatial coverage is too weak to accurately identify sources of emissions (they characterized emissions only on a global scale), or the spatial coverage capacity is too weak (they were not able to observe large enough areas). A major problem until the launch of the EMIT instrument in July 2022 (Earth Surface Mineral Dust Source Investigation) started on International Space StationInternational Space Station Which, according to a new study published in the journal ScienceCapable of identifying sources of carbon dioxide and methane emissions at scales less than 60 metres.

Observing greenhouse gas emissions from space

Deployed to the International Space Station (ISS) in July 2022, Emit is a spectroscopespectroscope Created by Imager NASANASAobserving in lightslights visible and near infraredinfrared, It is initially designed to measure the effect of dust suspended in the atmosphere on atmospheric temperatures and to identify the sources of their emissions (usually arid regions). According to the team of scientists, these characteristics also allow the instrument to accurately identify sources of carbon dioxide and methane emissions on the surface of our planet.

Fulfilling its initial purpose, the Emit Spectroscope’s first mission was aimed at observing the most emitting atmospheric dust – arid regions such as the Middle East. Using data collected by the spectroscope during its first 30 days of activity, the team of researchers precisely identified 65 sources of carbon dioxide and methane in the Middle East and Central Asia, primarily from oil fields and gas, Also come from processing facilities. wastewaste and power plants. The data collected by the spectroscope partly relates to regions whose exact emission rates are poorly known to scientists, which increases the uncertainties related to assessments of the global carbon balance.

In just 30 days, the instrument was able to cover an area larger than the size of South Africa, demonstrating its high capacity for spatial coverage, while managing to identify emission sources at a scale of less than 60 metres. . Researchers plan to capture emissions from more than 1,600 power plants around the world during the first year of the mission. Future greenhouse gas emissions data from Emit will be made publicly available.