EARLIER this year, NASA scientists set foot on a new Tongan island, one of only three to have erupted in the last 150 years which survived more than a few months. Until then, they had only seen it through satellite imagery.
Satellites are transforming the way we see – and map - the Earth.
With satellite imagery, maps can now provide complex layers and meaning that act as a guide through both the physical and human elements of the Earth’s surface.
A new project to map blue carbon in Papua New Guinea, Fiji and Indonesia is an example of how far satellite imagery can take us.
In May this year, Australia strengthened its deep and enduring engagement with the Pacific to build a more climate-resilient region, committing to the new CSIRO and Department of the Environment and Energy (DoEE) project.
It is an example of how data from satellite services - Earth Observations (EO) - can benefit end-users in the Pacific Islands. All while forming new partnerships between people, institutions and nations along the way.
What is blue carbon?
Blue carbon is carbon that is captured by marine and coastal ecosystems, such as mangrove forests and seagrass meadows.
These systems play an important role in mitigating climate change, sequestering atmospheric carbon at a faster rate than much larger, land-based forests.
Though coastal habitats comprise less than five percent of the land, their sediments store about half the carbon in the oceans.
However, carbon is released back into the atmosphere if the ecosystem is damaged, either through development or climate change impacts. Approximately 1.02 billion tons of carbon dioxide are released from degraded coastal ecosystems every year.
Dr Neil Sims is a remote sensing research scientist at CSIRO. He says blue carbon forms a significant part of the carbon budget across the Pacific Islands.
“This means looking after coastal areas is bang for buck,” Sims says.
Mapping challenges
The blue carbon mapping project will contribute to the sustainable management and protection of mangroves and seagrasses in Fiji, PNG and Indonesia.
However, these areas are often difficult to access and therefore map. And you can’t manage or protect what you don’t know.
Satellite imagery can help zoom in on these areas, providing data that reveals Earth’s physical features. But a good map still needs validation with field observations.
Old maps, new tricks
In March this year Sims stumbled across hardcopy, hand-drawn maps of mangrove areas in Fiji. Dating back to the 1970s, they are a treasure trove of old maps that can be re-purposed with a bit of new tech.
Sims says the maps were found in “A Mangrove Management Plan for Fiji” by Dick Watling—books prepared in a joint project of the Fiji Government and the South Pacific Commission.
Sims compared these maps with recent high-resolution Google Earth images.
Surprisingly, “the patterns on these 40-year old maps matched pretty well with the patterns in the Google Earth images captured in the past couple of years—except in areas with high flow, near estuaries and inlets, or developments such as new resorts,” Sims says.
Sims, Brent Murray (a visiting student from the University of Winnipeg in Canada) and Helena Zhong (a year 10 student on work experience from a Melbourne high school), have since scanned the maps and aligned them with the Google Earth images.
The maps are a major boost for the blue carbon mapping project and are now being used to guide the classification of mangroves in recent images from the Sentinel satellites.
“Such detailed local knowledge to validate recent satellite data can build a clearer picture of Fijian mangrove environments and their change over time,” Sims says.
He adds that the product of this combination will guide other sampling with satellite images throughout the region.
“These new maps will inform comprehensive updated mangrove management plans for Fiji and throughout the Pacific Islands.”
Human dimensions
When looking at the function of an ecosystem, the human element can’t be ignored. Coastal communities depend on seagrass meadows and mangrove forests for their livelihoods.
For example, these areas are used for mangrove wood and harvesting mud crabs, says Sims.
Pacific islanders reinforced the socioeconomic value of these ecosystems at a CSIRO-hosted workshop in Brisbane late last year.
“How does a small remote island in the vast Pacific Ocean fend for itself and effectively manage its environment in the face of climate change? EO can help,” Dr Alex Held told the workshop. He leads the CSIRO Centre for EO and was also a workshop convenor.
It was the outcomes of this workshop that inspired the March 2019 trip to Suva, as well as Port Moresby, to scope the blue carbon mapping project.
A team of seven CSIRO and two DoEE staff hosted targeted workshops in both locations with key Pacific partners, such as experts in planting mangroves and modelling carbon in mangrove communities. Together, they refined project objectives and selected the best sampling locations for their proposal.
EO challenges
Just as satellite services can help manage local ecosystems, EO data is important for further decision-making around future food, health, social and economic needs.
The Brisbane workshop addressed the challenges of using and applying EO in the Pacific region. There were representatives from 16 Pacific Island countries, as well as Australia, France, the United Kingdom, the USA and Japan, along with a range of service-provider organisations.
Day one of the workshop included a whopping 33 presentations, but “these were a fantastic opportunity to hear directly from the island states about their most important challenges and needs”, Sims says.
“For instance, internet coverage across many island states is actually quite good,” he says. “But it is expensive. Many countries have satellite internet.”
Australia is currently increasing its engagement in the Pacific region, especially in supporting technological advances in environment and natural resource management.
The Data Cubes CSIRO developed with Geoscience Australia are one technology that can significantly lower internet usage costs by reducing the amount of data transferred over the internet.
But, Sims says, another challenge is identifying key players. “Who should host a decision-support tool?” he says. “What are the lines of communication? Where can it be best placed to get to the people who need it?”
He says this is where partners—such as the DoEE—are crucial. While CSIRO deliver the science and technology, DoEE helps navigate the policy setting.
Stronger, together
In hosting EO workshops and collaborating on the blue carbon mapping project, CSIRO aims to support in-country carbon-mapping capacity and custodianship of data.
“The effective use of EO information can have a transformational impact on many countries’ greatest challenges,” says Sims.
“Supporting the resilience of our nearest neighbours to the impacts of climate change also improves Australia’s national security.
“We’re providing skills and technology to empower those who are hit hardest by climate change to use and apply this data.”
Given that part of that includes snorkelling off the coast of Suva to look at the seagrass beds in 29-degree C water, “the fieldwork could be worse!”