The Unsung Heroes of Battle
Climate Change, Global Warming, the Greenhouse Effect, call it what you will, everyone is talking about it; and with good reason, its potential impact on the planet is immense. Venus, about the same size as planet earth, once had an atmosphere that was similar to ours. Then about 700 million years ago, an out of control greenhouse gas effect took over. Now, its atmosphere is 96% CO2 and the surface temperature is circa 460oC. A truly salutary warning. Not that any of us will be around in 700 million years, but most of us will be around in 2030, when, according to Climate Central, multiple cities around the world including Venice, Amsterdam, New Orleans, Ho Chi Minh City and Kalkuta will be below the tideline.
But what you hear far less about is the role that satellites are playing in fighting climate change. Call them the unsung heroes of the battle. In fact, it’s fair to say that without satellites, we would have no idea of the either the scale or the trajectory of the damage. Satellites are fundamental to both identifying the size of the problem, and measuring the numerous changes taking place and of course for detecting the impact of any remedial action that is being taken.
As Krystal Azelton, who in 2018 was listed on SSPI’s “20 Under 35” people to watch, said: “Satellites were absolutely key in understanding we had a climate crisis . . . We are seeing vast improvements . . . in data sharing and access and the push to have open access to government data around the world is huge.” Krystal is the Director of Space Applications Programs at the Secure World Foundation, a non-profit Washington D.C. think-tank.
Monitoring the Earth’s atmosphere is not a new phenomenon, the first satellite to do was Nimbus III launched by NASA in 1969. Today there are hundreds of satellites orbiting the earth collecting vast amounts of data, all of them way more sophisticated than Nimbus III. Some of these are operated by government funded bodies and international organizations, but there are now also many, many commercial companies whose motives may be less altruistic, who nevertheless are making a very significant contribution to our knowledge and capabilities. Some of them, like Planet for example, are also working with government entities and non-profit organizations. This is so important, as without easy access to data, companies and countries won’t be in a position to pinpoint the issue and take remedial action, As Krystal pointed out: “We are seeing vast improvements . . . in data sharing and access” and “the push to have open access to government data around the world is huge.”
The major cause of global warming, is the amount of heat from the sun trapped in the Earth’s atmosphere. Carbon dioxide (CO2) is the most prevalent gas responsible for this, so levels of CO2 is one of the key indicators being monitored. Initially, it was only possible to look at overall levels, but increasing sophistication means that it is now possible to identify carbon dioxide emissions by locale. NASA’s OCO-3 a satellite launched in 2019 and attached to the International Space Station is one example of a satellite doing just that. It gathers information to let scientists see exactly where CO2 is accumulating, and how that is influenced by factors such as temperature, pressure, volcanic eruptions and even plant growth.
Taking that one step further is the Tropospheric Monitoring Instrument (TROPOMI). TROPOMI is mounted on Copernicus Sentinel-5P, a satellite belonging to the European Space Agency (ESA) and the Netherlands Space Office. One of the things that TROPOMI measures is nitrogen dioxide (NO2). This is relevant, as the presence of NO2 distinguishes CO2 caused by burning fuels, from natural sources of CO2, which aren’t accompanied by NO2.
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Methane, also present in the earth’s atmosphere, absorbs even more heat than CO2. It is less prevalent than CO2, but nevertheless its concentration has doubled in the last 70 years. Given its greater potency, reducing methane levels can have a more immediate impact on global warming. Carbon Mapper is a public-private partnership created to pinpoint methane emissions. Members include NASA’s Jet Propulsion Labs, Planet, the State of California and Arizona State University. The satellites that will be launched in 2023 will have the ability to identify methane emissions down to individual buildings. Other entities working to pinpoint methane emissions include GHGSat, a Canadian company that uses two satellites to pinpoint leaks.
Monitoring climate change involves more than pinpointing and measuring greenhouse gas emissions. Observing the rise in sea temperature, the thickness of ice and the rate that it’s melting are all part of the equation. But for me, the most surprising thing being monitored by satellites is the health of trees. Healthy trees, absorb CO2, unhealthy trees do not, and may even emit CO2. The optical sensors on Landsat 9 are so sensitive that they can distinguish 16,000 shades of a given wavelength color, which provides a wealth of information about the health of vegetation. Valuable information in the war against climate change.
Our dependence on satellites in the war against global warming, actually goes further than this. Satellites are playing an increasing role in disaster mitigation, but that needs to be the subject of another blog.
This blog by Elisabeth Tweedie, Founder of Definitive Direction, first appeared in the SSPI-WISE blog at www.sspi.org/cpages/the-unsung-heroes-of-battle.