Space technology: an exploration of its potential in understanding and mitigating climate change - Vol 5 Sneak Peek

In the fight to mitigate climate change, Satellite observations offer invaluable insights on the Earth system – but greater investment in education and research is necessary.

Article by: Izzy Short

Artwork by: Nathalie Dickson

In the fight to mitigate climate change, climate scientists are looking to increasingly more innovative solutions. Space technologies offer great promise – for years, satellite observations have offered invaluable insights on the Earth system – but to maximise their potential, greater investment in education and research is necessary.

With Nationally Determined Contributions (NDCs) – a country’s proposed contribution towards the goals of the Paris Agreement – projected to fall short of the ambitious reduction in emissions necessary to limit global warming to 1.5 degrees Celsius, scientists are emphasising the imperative for more efficient and innovative solutions to climate change mitigation. Beyond more intuitive terrestrial solutions, such as reforestation and conservation agriculture, space technologies are emerging as an underutilised resource, with the potential to complement and optimise existing initiatives. 

Observing and modelling the Earth 

Since their first deployment more than 60 years ago, Earth Observation satellites have revolutionised our understanding of the Earth and its evolution under anthropogenic climate change. At present, more than 150 of these satellites orbit the Earth, collecting data for 55 standardised Essential Climate Variables (ECVs). These variables are crucial to the detection and attribution of climate change, and include measurements of surface temperature and atmospheric greenhouse gas composition.

A significant advantage of using satellites to obtain remote measurements is that they can provide data on a regular basis, with near-global coverage and minimal intrusion. 

By contrast, in-situ observations - taken at the location of interest, rather than remotely - are often spatially limited, with most measurements being taken in North America and Europe. This poses challenges for the assimilation and validation of satellite data – a process which often involves comparing satellite data against in-situ measurements. This concerning disparity often manifests itself in a cold bias, whereby satellites underestimate temperatures due to the use of unrepresentative data of the Global South. 

Despite these limitations, by using satellite data as input for developing and validating climate models, we can achieve more reliable projections of climate change when compared with in-situ measurements alone. Resulting projections indicate that unless we achieve negative emissions, we are likely to exceed the optimistic target of limiting global warming to 1.5 degrees Celsius by 2100. Consequently, it is important that we explore the use of innovative and efficient solutions to climate change mitigation, such as space technologies.

Space-based solar geoengineering

Following the eruption of Mount Pinatubo in 1991, scientists observed a significant and prolonged cooling of the Earth’s surface. In the 15 months following the eruption, a 0.6 degree Celsius drop in global temperature was measured. 

This observation is attributable to the reflective nature of the sulphate aerosols produced and injected into the stratosphere by the eruption. In particular, these aerosols act to increase the Earth’s albedo – that is, the proportion of incident light reflected by a surface – producing an almost immediate and significant cooling. 

Whilst scientists have long known of the impact of volcanic eruptions on global weather patterns – 1816, the year following the eruption of Mount Tambora, is well known as the “Year Without a Summer” – the eruption of Mount Pinatubo provided the opportunity to validate climate models against well monitored real-world scenarios. Not only did this help consolidate understanding of the radiative forcings resulting from volcanic eruptions – namely, the Earth’s energy imbalance which produces the observed cooling – it served as impetus for geoengineering research.

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