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Satellites for monitoring climate change

“If you can’t measure it, you can’t manage it”, said María Fernanda Espinosa Garcés, President of the United Nations General Assembly at the COP 24 in Katowice Poland, summing up how crucial satellites are for measuring climate change.

Satellite measurements of Earth’s temperature, greenhouse gas emissions, sea levels, atmospheric gases, dwindling ice and forest cover etc, are essential for improving the understanding of Climate change and predicting future of the Earth.

Innovation such as miniaturization of sensors, high-speed data transfer, and upgraded storage capabilities have made satellites an integral part of the climate change mission. It is simply inconceivable to assess climate change sans insights provided by satellites. Without precise data and other inputs provided by satellites, environmentalists and scientists won’t be able to understand, analyze and predict the impact of climate change, and policymakers won’t be able to formulate effective strategies.

Using an array of satellites, organizations like NASA, NOAA and ESA monitors ocean conditions, clouds, temperature, sea levels and heat content, to get information on how fast Earth’s temperature is changing.

ESA map shows ocean salinity

Satellite data provides authoritative information about more than half of the 50 crucial climate change variables. These insights include satellite radar altimetry, which measures distance between a satellite and the earth’s surface and gives us precise information about sea levels. Atmospheric chemical composition and greenhouses gases like Methane are also measured using satellites. Currently, there are around 162 satellites in-orbit that measure the various indicators related to climate change.

New generation satellites have enhanced optical and temporal resolutions that have improved weather forecasting, climate modeling and the ability to obtain real-time details. Within the next five years, many new satellite missions will be launched, including Eumetsat’s second-generation polar-orbiting satellites, third-generation Meteosats and Chinese satellites.

Dwindling ice covers

Though there are programs to monitor at both the poles, the biggest news came in 2017 when a huge iceberg broke away from the Antarctica landmass. This changed the map of the world forever.

Satellite data is crucial for systematic monitoring of ice sheet volume change, mass balance, and sea-level rise. The first study on change in Antarctic ice sheet patterns used data from Copernicus Sentinel-3 Delay-Doppler altimeter. Declining ice cover also leads to rise in sea levels. Satellite imagery shows the decrease in ice caps in Antarctica. In Greenland, the ice sheet is melting six times faster as compared to 1980s.

The Sentinel-3 mission is mainly for applications for the ocean and coastal monitoring, numerical weather and ocean prediction, sea-level change and sea-surface topography monitoring, ocean primary production estimation and land-cover change mapping.

Copernicus Sentinel-3 maps Antarctic Ice Sheet elevation change

NASA satellites ASTER and Landsat are used to track a decrease in ice caps and level of glacial melting. The series of images by these satellites help scientists map changes in polar ice caps over time.

Copernicus Sentinel-3, Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) and the ICESat-2, provide information about vanishing ice caps in the two polar regions of the Earth.

Sea ice of different thickness and bumpiness is broken up by the cracks between floes, called leads, in this graph of photon returns from ICESat-2 as it orbits over the Weddell Sea in Antarctica. Image Courtesy: NASA Earth Observatory/Joshua Stevens

Launched in September 2018,  NASA IceSat-2 is the most sophisticated satellite for measuring ice. It points six laser beams at ice sheets in the Arctic and Antarctic regions.

Pinpointing emissions and pollution

Copernicus Sentinel-5P, launched by ESA (European Space Agency) in October 2017, is said to be the most advanced pollution monitoring satellite in the world. It tracks carbon monoxide, nitrogen dioxide, and ozone, along with aerosol. It also monitors formaldehyde, which is one of the sources of carbon monoxide.

Sentinel-5P image shoes NO2 concenteration worldwide

In January 2009, Japan launched the world’s first satellite dedicated to greenhouse monitoring — Greenhouse Gases Observing Satellite (GOSAT). It measures CO2 and methane densities from 56,000 locations around the world. In October last year, the Japan Aerospace Exploration Agency (JAXA) launched GOSAT-2 to generate even more precise data.

By early 2020, US is scheduled to launch the Geostationary Carbon Observatory (GeoCarb) to track global carbon cycle from a geostationary orbit, making it the first NASA satellite to measure methane near Earth’s surface. GeoCarb will gather 10 million daily observations of the concentrations of carbon dioxide, methane, and carbon monoxide.

Deforestation

Deforestation is among the leading causes of global warming, accounting for around a quarter of global greenhouse gas emissions. As per researchers, deforestation in tropical rainforests produces more carbon dioxide than most vehicles in the world. In countries like Brazil and Indonesia, depleting forest cover is the main reason for greenhouse emissions.

NASA satellite imagery showing deforestation in Brazil

The state of Rondônia in western Brazil, which was once home to 208,000 square kilometers of forest (about 51.4 million acres), an area slightly smaller than the state of Kansas, now has become one of the most deforested parts of the Amazon, according to the NASA Earth Observatory.

Ocean pollution

satellites for climate change
NASA’s Landsat-8 satellite image showing pollutants and organic matter flowing into the Atlantic Ocean

Oceans too are bearing the brunt of human activities and water pollution is leading to the death of many aquatic species. Satellites are used to monitor the discharge of plastic in the ocean. It is estimated that around eight million tonnes of plastic is dumped into the sea every year.  Satellite imagery shows the havoc unleashed by plastic dumping.

Coral Reefs

Coral reefs support the most extensive biodiversity of any ecosystem globally and support close to 5OO million people in poor countries. Around 25% of marine life is supported by coral reefs but in the past 30 years, more than half of the world’s corals have been destroyed. It is being estimated that going by the current alarming rate, more than 90% of the world’s corals will cease to exist in the next 50 years

NOAA Coral Reef Watch

Coral Reefs are threatened due to massive global warming and greenhouse gas emissions. As per UNESCO, coral reefs in World Heritage sites would disappear by the end of the century. Satellite imagery shows the extent of coral reef bleaching.

Desertification

NASA imagery showing desertification in Mali

Desertification is a type of degradation of land due to which land becomes more arid. Global warming is increasingly leading to desertification. Each year around 12 million hectares of productive land become barren every year due to desertification and drought alone according to UNCCD. Satellite imagery shows the extent of desertification.