6 ways satellites are helping to monitor our changing planet from space

This article was first published on 6 March 2024 and updated on 16 May 2024.

When ERS-2 came spiralling down to Earth in March, it wasn’t just another satellite burning up in the atmosphere. ERS-2 was the last surviving of two satellites scientists reverently call “grandfathers of Earth observation in Europe”.

Launched in the early 1990s by the European Space Agency (ESA), the two ERS (Earth Remote Sensing) missions offered scientists new ways of studying our planet’s atmosphere, land and oceans. This included monitoring the sea ice, deforestation, ozone levels and many other aspects relating to our planet’s health.

And what they revealed gave cause for great concern, according to the BBC. While scientists believed the polar ice sheets were stable and unlikely to be affected by climate change for decades, ERS information showed they were already undergoing dramatic change.

ERS-2 completed its mission in 2011, having laid the foundations for much of the Earth observation work going on today from space. So, what about ERS’ children and grandchildren?

NASA’s PACE mission is the latest among ERS’ heirs. PACE stands for Plankton, Aerosol, Cloud, ocean Ecosystem. Launched in mid-February, the satellite will provide data about microscopic organisms in the water and particles in the air that are key to many processes affecting our planet, in particular climate change.

PACE’s instruments, among others, will enable scientists to track the distribution of phytoplankton, which plays a key role in the global carbon cycle as it absorbs CO2 and converts it into cellular material. It can also be used to keep tabs on the health of fisheries, harmful algae growth and other changes in our oceans.

Other equipment will monitor the impact of sunlight on atmospheric particles, clouds and air quality.

The International Space Station (ISS) is uniquely positioned to monitor our planet as it’s able to cover 90% of the Earth’s population. As it progresses along its orbit, it experiences 16 sunrises and sunsets a day.

Astronauts’ photography, for example, is one major monitoring source for tracking storms or volcanic eruptions in real time. Adding to this is an array of instruments placed on the outside of the space station, many of which collect climate data, according to NASA. Data collected on the ISS covers anything from mineral dust particles in the atmosphere as they can affect warming, cooling and air quality through sea surface temperatures and atmospheric gases like ozone.

Shoebox-sized nano-satellites, called CubeSats, might be described as the ERS missions’ grandchildren.

They can be deployed from the ISS to test new climate science experiments and extend the station’s reach in climate change science to a much wider area.

CubeSats are modular, highly integrated and use hardware available off-the-shelf. This makes them scalable to the specific needs of a mission. They are also standardized, making them easier to fit into the standard transport containers on launch vehicles. This equates to more launch opportunities and lower costs.

The Sea and Land Surface Temperature Radiometer (SLSTR) was launched as part of ESA’s Earth observation project, Copernicus. SLSTR systems are installed on two of its Sentinel satellites launched in 2016 and 2018, with two more missions planned for 2024 and 2025. Designed to continue the observation work undertaken by the ERS twins in the 1990s and early 2000s, SLSTR systems focus on ocean surface topography as well as land and sea surface temperature.

With the forthcoming launches, scientists will have 40 years’ worth of sea surface temperature data available, helping them to understand long-term climate trends. What is more, the satellite equipment will help establish a baseline and enable us to measure the impact of decarbonization policies as we approach 2050 and beyond.

Launched in early March 2024, MethaneSat is the latest addition to the growing array of technology monitoring our planet's health. The aim is to locate methane leaks from oil and gas operations across the planet – as well as emission loss rates – and track their evolution over time.

Methane, which is the main constituent of natural gas, is the second-largest contributor to global warming after CO2. Its concentration in our atmosphere has more than doubled over the past 200 years.

Developed by US non-profit the Environmental Defense Fund with the New Zealand Space Agency, MethaneSat aims to bring accountability to the oil and gas industry. It will also help the sector prepare for new methane regulations in the EU and US.

A fourth global coral bleaching event was confirmed in April 2024, based on sea-surface temperature data captured by National Oceanic and Atmospheric Administration (NOAA) satellites. Coral bleaching is extensive across the Atlantic, Pacific and Indian Ocean basins, says the NOAA, which has been monitoring ocean temperatures since 1985.

But the climate crisis isn't the only culprit here. Pollution from wildfire or agricultural runoff can "impede coral growth", as can harmful algae and extreme rainfall, says the NOAA's Ryan Vandermeulen. The next generation of Earth observation satellites, called GeoXO, will be able to detect pollution in rivers and oceans, measure air quality hourly and even "see where turbulence is starting", says Pam Sullivan, GeoXO Programme Director at NOAA. These satellites should be launched in the early 2030s.

With the vast amount of data on Earth’s climate being generated both on the planet and in space, a key ambition of the World Economic Forum is to bring these together in an open, online resource. Its Global Ecosystems Atlas is intended to provide a comprehensive view of the world’s ecosystems to help set conservation targets, monitor regulatory compliance, and design the food, health and mobility systems of the future.

By 2030, the Earth observation (EO) field is expected to contribute over $700 billion to the global economy – and reduce annual greenhouse gases by two gigatonnes, according to a new Forum report. Furthering the dialogue on how EO data can be leveraged to generate value for business, people and the planet is the goal of the Forum's Earth observation community.