Science·What on Earth?

Satellite data is helping us understand our changing planet

In this week's issue of our environment newsletter, we look at how satellite data can help us learn more about our environment and examine what Canada agreed to at the COP26 climate summit.

Also: The evolving U.S. electrical grid

(Sködt McNalty/CBC)

Hello, Earthlings! This is our weekly newsletter on all things environmental, where we highlight trends and solutions that are moving us to a more sustainable world. (Sign up here to get it in your inbox every Thursday.)

This week:

  • Satellite data is helping us understand our changing planet
  • The U.S. electrical grid is evolving
  • What did Canada agree to at COP26?

Satellite data is helping us understand our changing planet

(Kel Elkins/NASA)

Given the interest in carbon capture in the broader fight against climate change, a recent paper tallied up all the carbon held by the plants and soils covering Canada's vast landscapes. It was a herculean task, given that Canada has some nine million square kilometres of land. 

Monitoring all those trees, plants and soils over such a large area only recently became possible because of advances in a technology called lidar (or light detection and ranging), which could help Canada protect those important carbon stores and combat global warming.

Lidar is a laser technology that can be used to build a three-dimensional picture of the landscape. The carbon study used data from lidar mounted on a satellite orbiting the Earth, shooting laser beams down at the surface and measuring the speed at which those beams are bouncing back. 

This was then used to calculate the height of plants and trees all over Canada, making it possible to estimate the carbon stored in those ecosystems.

Lidar has been around since the 1960s, but the level of detail in the carbon study was not available before.

"This is definitely a huge jump technologically," said Valerie Casasanto, the outreach co-ordinator at NASA's ICESat-2 satellite project, which launched in 2018. Data from the satellite, whose sole instrument is a lidar laser, was used in the carbon study. 

"[The satellite's lidar] gets a much, much higher precision. You can measure within about four millimetres of difference and changes."

The primary scientific objective of ICESat-2 is to measure the changing cryosphere — including continental ice sheets in Greenland and Antarctica, glaciers, ice caps and sea ice around the poles. But Casasanto says as the satellite collects reams of richly detailed data from around the planet, researchers have found their own uses for it.

That includes more than 100 studies and counting, including one that looked at the migratory patterns of penguins in the Antarctic Peninsula. 

Previously, satellite imagery could only measure sea ice during sunlit months in the region, but ICESat-2's laser beams work in the darkness as well, allowing scientists to figure out where there's sea ice and open water in the winter.

Lidar is also turning up in other climate-related applications. A groundbreaking study on methane emissions in B.C. used lidar mounted on an airplane to "see" plumes of the gas. Methane, the main component of natural gas, leaks from oil and gas production sites but is difficult to detect because it is colourless and odourless. 

Ferreting out such leaks is key because methane is 70 times more potent than carbon dioxide as a greenhouse gas and a key target in the fight against climate change.

Data from ICESat-2 is used widely because it is made freely available. The project is fully funded by the U.S. government, and its planned lifespan was three years.

It is now about two months beyond that. Casasanto says the data mission could run for seven years based on the fuel onboard and possibly longer with some adjustments — providing important information on our changing planet as it enters an increasingly uncertain climate future.

Inayat Singh

Reader feedback

One theme that comes up frequently in reader emails is the idea that overpopulation is a major contributor to global warming. 

Nicole Mortillaro did a deep dive on this issue in 2019, and the reporting remains relevant. The main takeaways from the piece are:

  • Population is a factor in climate change, but only one of many.
  • Global birth rates are in fact declining.
  • It is key to look at per capita emissions: richer countries such as the U.S. and Canada, for example, produce more emissions per person than China or India.

To quote Kathleen Mogelgaard, a U.S.-based researcher who studies population dynamics and climate change, "Just because we slow population growth, if we continue to use coal-fired power plants to generate electricity or if we continue to cut down forests at the rate that we're cutting down forests, those are going to be challenges regardless what the population is."

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Old issues of What on Earth? are right here.

There's also a radio show and podcast! Atmospheric rivers, landslides and flooding have brought British Columbia to a halt, as the province enters a state of emergency. What On Earth host Laura Lynch hears how climate change ensures more of these events in the future and what can be done to prepare. What On Earth airs Sunday at 12:30 p.m., 1 p.m. in Newfoundland. Subscribe on your favourite podcast app or hear it on demand at CBC Listen.

The Big Picture: The evolving U.S. power mix

For all its environmental shortcomings, Canada can say that its electrical grid is fairly clean — it's about 80 per cent emissions-free (largely because of an abundance of hydro power). The situation stateside is less green. As the graph below on the left shows, the U.S. grid is more dependent on fossil fuels, with large amounts of natural gas (38 per cent) and coal (23 per cent) in the mix. But the graph on the right shows how things are changing: new power capacity expected on the grid by the end of this year is heavily weighted toward wind, solar and battery storage.


Hot and bothered: Provocative ideas from around the web

What did Canada agree to at COP26?

(Phil Noble/Pool/The Associated Press)

Canadian officials made a flurry of speeches, announcements and declaration signings at the COP26 climate conference in Scotland. But what exactly did they say, do and sign? Here's a closer look.

Commitment to end public financing of fossil fuel projects

Canada was one of 30 countries that signed a statement to "end new direct public support for the international unabated fossil fuel energy sector by the end of 2022, except in limited and clearly defined circumstances that are consistent with a 1.5 C warming limit and the goals of the Paris Agreement."

The countries also say they will "prioritize our support fully toward the clean energy transition."

"That was really significant," said Julia Levin, senior climate and energy program manager at Environmental Defence, a non-profit environmental advocacy group.

A report from the group found Canada spent $18 billion on financial support for the fossil fuel industry last year. Of that, $13.6 billion came from Export Development Canada, a government agency that offers services such as loans and insurance to the oil and gas industry.

However, EDC said it provided only $8.1 billion to the oil and gas industry in 2020 and just $2.7 billion in the first half of 2021. Levin said most of that EDC support is for domestic projects, but the new agreement should eliminate about one-third of that financing.

While countries have previously committed to cutting financial support for coal, Levin noted this was the first time they have done so for oil and gas.

"That's an important turning point in the conversation," she said.

Call for a global carbon tax

Prime Minister Justin Trudeau urged all countries to agree to a global price on carbon. Trudeau said he wanted to see 60 per cent of global emissions covered by a carbon tax by 2030 — up from the current 20 per cent.

Lauren Touchant, a postdoctoral researcher with the Centre on Governance and the Centre for Environmental Law and Global Sustainability at the University of Ottawa, said the call for a global carbon tax was "a major contribution" from Canada.

Levin agreed, calling it "encouraging" that Canada is showing leadership on carbon pricing.

Oil and gas emissions cap

Trudeau also told COP26 that Canada will impose a cap on oil and gas sector emissions "today" to ensure they "decrease tomorrow at a pace and scale needed to reach net-zero by 2050."

It was something the Liberals had promised during the summer election campaign. So far, however, the government hasn't said how this will work.

"That's one commitment where the devil really is in the details," Levin said.

If the regulations are stringent enough, they could curb and ultimately reverse oil and gas expansion, she said. But alternatively, they could be "complete greenwashing and lead to nothing."

Commitment to end deforestation by 2030

Canada was one of more than 130 countries that signed a declaration to "halt and reverse forest loss and land degradation by 2030." The declaration covers more than 3.6 billion hectares of forest around the world.

However, 40 countries, including Canada, signed a similar agreement in 2014, The New York Declaration of Forests, and deforestation has increased 40 per cent since then.

Like that pledge, the new declaration is non-binding, although it has been signed by more countries. However, at least two Canadian ecosystem scientists say it's "less ambitious" because it aims only to end net deforestation, where forests aren't replanted.

"We really need to see clear commitments that include specific language," said Tegan Hansen, a forest campaigner with the advocacy group

Global Methane Pledge

The U.S. officially launched the Global Methane Pledge at COP26 to cut emissions of the greenhouse gas methane by 30 per cent from 2020 levels by 2030.

It prompted Canada to confirm its support for the pledge, first announced in mid-October, which included a commitment to reduce Canadian methane emissions from oil and gas to 75 per cent below 2012 levels by 2030.

Canada has yet to say how it will meet its targets, Touchant noted.

Zero-emissions cars, trucks

Canada also made some commitments relating to electric vehicles:

Emily Chung

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Editor: Andre Mayer | Logo design: Sködt McNalty

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