What is the Keeling Curve and what does it tell us about the health of the planet?

Our planet is changing. So is our journalism. This weekly newsletter is part of a CBC News initiative entitled "Our Changing Planet" to show and explain the effects of climate change. Keep up with the latest news on ourClimate and Environment page.

Sign up hereto get this newsletter in your inbox everyThursday.

This week:

• What is the Keeling Curve and what does it tell us about the health of the planet?
• Finland's world-beating climate ambition
• As wildfire season approaches, new studies show air pollution linked to severe health outcomes

What is the Keeling Curve and what does it tell us about the health of the planet?

On June 3, The Scripps Institution of Oceanography and the National Oceanic and Atmospheric Administration (NOAA), which tracks global carbon emissions, made another dire announcement.

The American agency said that atmospheric carbon dioxide peaked in May at an average of more than 420 parts per million, "pushing the atmosphere further into territory not seen for millions of years."

This measurement is often reflected in something called the Keeling Curve, a graph that illustrates the changes in atmospheric carbon dioxide (CO2) over time.

The graph gets its name from Charles David Keeling, the American scientist who developed the accurate way of assessing atmospheric CO2. (He died in 2005.)

What the graph has steadily shown since its inception in 1958 is a rapid increase in atmospheric CO2 and, as everyone knows by now, more CO2 means more global warming.

The Keeling Curve has been instrumental in measuring the rate of CO2 in the atmosphere, but that wasn't always the case.

Around the turn of the 20th century, some scientists theorized about the potential link between burning fossil fuels and increasing carbon dioxide, but it was still poorly understood.

Keeling developed his unique and incredibly precise instrument to measure CO2 in 1953, and in 1956, his invention caught the attention of a few scientists, including ones at the U.S. weather bureau and the Scripps Institution in California. A global CO2 monitoring program was proposed, with stations set up at Mauna Loa in Hawaii and the South Pole. Today, there are hundreds of these analyzers set up around the world.

So, how does it work?

First, scientists collect air in a glass flask, which is taken to a lab and put through an infrared analyzer. Using different wavelengths, scientists can determine how much CO2 is in the sample and even tell where it came from, be it an ocean, plant or vehicle.

The analyzer measures the amount of carbon dioxide molecules in a million parts of air. When the first reading was taken at Mauna Loa in March 1958, the measurement was 313 parts per million (ppm), meaning that in one million particles of air, there were 313 particles of carbon dioxide.

In the years after Keeling devised his measurement system, Scripps managed to gather more data on CO2 concentration by collecting ice cores from the Antarctic, which allowed it to extend the graph as far back as 800,000 years ago, to a time when CO2 was just 250 ppm.

The early use at Mauna Loa also revealed something quite interesting: CO2 concentration varied not only throughout the day, but also seasonally. In the spring and summer, the planet removed CO2 from the air for plant growth and returned it to the atmosphere in the winter. Essentially, it showed the planet breathing.

Since then, the Mauna Loa location has become the leading location for analyzing atmospheric CO2.

"The Mauna Loa record developed iconic status, because it was such a brilliantly precise and just overwhelmingly clear signal of human impact," said Ralph Keeling, Charles David Keeling's son and a professor of geochemistry at Scripps.

Despite the many analyzers around the world, Ralph Keeling said the Mauna Loa location is still one of the best locations on the planet for these observations.

"It's on an island on a mountain in the middle of the ocean," Keeling said. "It's like a probe sticking into this remote part of the atmosphere. So the air that it sees is really characteristic of a large chunk of the world."

For all its technological innovation, what's most profound about the Keeling Curve is what it tells us. The upward trend in carbon concentration is undeniable. While it was 313 ppm in 1958, today it has soared to 420 ppm. Ralph Keeling said it's likely we will reach 450 ppm within the next decade.

The consequences? More global warming. More severe weather, including droughts, heat waves and floods.

Canada has its analyzers, which have shown a steady rise as well. According to Environment and Climate Change Canada (ECCC), from 1976 to 2020, the annual average CO2 concentration rose by 24 per cent, from 333.4 ppm to 415 ppm. ECCC notes that annual changes in CO2 are in line with the changes that have been observed globally.

Ray Nassar, a research scientist at ECCC whose area of research focuses on greenhouse gas measurements, said that while the Keeling Curve is important, so is being able to measure emissions closer to home.

"If we want to be able to address climate change, which I think most of us do want to do, then we have to understand what's going on with our own emissions," Nasser said. "And people always say you can't manage what you can't measure."

One of the key takeaways from the Keeling Curve is that the world isn't taking action fast enough, Ralph Keeling said.

"It's a bottom line on the collective effort to slow the problem," he said. "And it shows that we haven't done anything near enough yet."

Nicole Mortillaro

Reader feedback

After our story on the efforts of the Heiltsuk Nation in Bella, Bella, B.C., to install heat pumps, a number of readers wrote in asking how green the community's electrical grid was, given the remoteness of the location.

What On Earth followed up with Qatuwas Brown, the communications manager of the Haizaqv Climate Action Plan. Here's what she said:

"The Haizaqv (Heiltsuk) Nation is on a remote limited microgrid utilizing hydro energy. Electricity for Bella Bella is provided by BC Hydro using electricity generated at the Ocean Falls Boralex Facility, which is within Haizaqv Territory. We basically buy power back from our own land and waterways. We also have local diesel generators for backup.

"Remote and non-integrated communities, like Bella Bella, pose unique challenges and opportunities in terms of energy supply and security. Our isolated microgrid may be prone to power-quality issues as supply infrastructure ramps up or down to accommodate changing loads. Due to the remote location, fuel for diesel generation must be shipped in, adding to the cost and vulnerability of providing electricity. An energy challenge we are tackling is the vulnerability of our microgrid and aging infrastructure."

Write us atwhatonearth@cbc.ca.

Old issues of What on Earth? are right here.

CBC News recently launched a dedicated climate page, which can be found here.

Also, check out our radio show and podcast. For 40 years, renowned Canadian photographer Edward Burtynsky has documented how people have damaged the planet. Ahead of his biggest show opening, What On Earth host Laura Lynch speaks with Burtynsky about why he thinks artists have "soft power" to help inspire climate action. What On Earth now airs on Sundays at 11 a.m. ET, 11:30 a.m. in Newfoundland and Labrador. Subscribe on your favourite podcast app or hear it on demand at CBC Listen.

The Big Picture:Finland's world-beating climate ambition

As the world becomes increasingly serious about tackling climate change, "net zero" has become a political mantra. Net zero means decreasing fossil fuel use and increasing carbon capture to the point where a region's emissions are (roughly) equal to what it stores. Canada, for example, has pledged to be net zero by 2050, enshrining it in legislation with the Canadian Net-Zero Emissions Accountability Act.

Over in Finland, lawmakers have a more ambitious goal: net zero by 2035. But they're not stopping there. The Nordic country recently announced that it wants to be the first to be net negative that is, sequestering more carbon than it produces and it wants to achieve this by 2040.

What On Earth11:01How Finland's new carbon negative plan can be 'a model and an inspiration'

Kati Kulovesi, Director of the Center for Climate Change, Energy and Environmental Law at the University of Eastern Finland on why her nation's new carbon negative target by 2040 is one of the most ambitious in the world.

The plan was born of a calculation that if we collectively want to limit global warming to 1.5 C above the preindustrial era, we can only afford to emit an additional 420 gigatonnes of carbon. Finland's climate change panel decided that to limit the country's own contribution to that figure, it needed to make deeper emission cuts.

While the strategy partially depends on reducing the fossil fuels in Finland's energy mix, it also relies on protecting one of its greatest natural assets: its forests. The fact that three-quarters of Finland is covered by trees gives the country a distinct advantage in carbon removal, but scientists say that as a result of deforestation in recent years, forests there have been emitting more carbon than they capture making land use a huge focus of the country's climate plans.

Hot and bothered: Provocative ideas from around the web

• Tests done by British company Emissions Analytics have revealed that the tires on modern vehicles produce more particle pollution than their exhaust systems. One contributing factor in this problem: vehicles have become heavier.

• Our colleague Chris Arsenault co-wrote this deep dive on the technology and tactics being deployed to stop illegal fishing near the Galapagos Islands.

• The increasing intensity of heat waves around the world has prompted some municipalities in the U.S. and Europe to categorize and name them, the way we do hurricanes, as a way to spur greater public awareness and government action to deal with them.

As wildfire season approaches, new studies show air pollution linked to severe health outcomes

As we head into wildfire season, experts are warning about the negative health impacts from air pollution and new research suggests it could exacerbate severe outcomes from COVID-19 and increase the risk of lung disease.

Doctors have previously made the link between fine particulate matter (PM 2.5) a pollutant emitted from anything burning and how inhaling it can exacerbate asthma, lung and heart disease.

According to a new study published in the Canadian Medical Association Journal, COVID-19 patients who live in areas exposed to common pollutants like fine particulate matter, nitrogen dioxide and ground level ozone are more at risk of severe outcomes like hospitalization, intensive care admission and death.

"There's really no threshold to say, oh, this is a safe level of air pollution. It really should be as low as possible," said study author Dr. Jeff Kwong, a family physician, preventative medicine specialist and senior scientist at the Institute for Clinical Evaluative Sciences in Ontario.

Kwong says he hopes the research will persuade policy makers to reduce pollution levels.

"We need to make sure we have good regulations to ensure that our air has a good quality, that it's not too polluted, because there are harms."

Researchers examined a cohort of 150,000 people who had COVID-19 in Ontario and assigned a level of pollution exposure to each individual based on where they lived from 2015 to 2019.

They compared the health outcomes of patients who live in areas with the most pollution to those who live in areas with the least and found the former were at higher risk of being admitted to intensive care. People with chronic exposure to particulate matter and ground level ozone also had more risk of hospitalization and death, the study found.

Scientists from the Research Institute of the McGill University Health Centre (RI-MUHC) found that even exposure to low levels of air pollution can be associated with poor lung function and chronic obstructive pulmonary disease (COPD).

Their study was published in the American Journal of Respiratory and Critical Care Medicine last week.

Dr. Courtney Howard, an emergency physician in Yellowknife and former president of the Canadian Association of Physicians for the Environment, says she's not surprised by the findings.

"Air pollution increases the levels of inflammation because the teensy, tiny little particles of air pollution can actually go through our alveoli, the barrier between our lungs and our blood, into our bloodstream and lead to inflammatory cascades."

Howard says air pollution can weaken the immune system and long-term exposure can make chronic diseases more likely.

According to a report published by The Lancet, pollution was responsible for an estimated nine million deaths worldwide in 2019, six million of which were attributed to air pollution.

Henderson says PM 2.5 comes from many sources, including gasoline in a combustion engine or fuel from a factory. Nitrogen dioxide is created by combustion from vehicles and ground-level ozone is created in the atmosphere when other pollutants interact with UV radiation, she says.

With climate change expected to prolong wildfire seasons, Henderson says she's expecting the amount of this pollution to increase.

Last year, B.C. saw record levels of extreme heat, which killed hundreds of people, and one of the most severe wildfire seasons.

"Disaster after disaster," Henderson said. "It's the cascading of these things together and the cascading of their impacts on health that is what stands out to me most right now."

Howard says everyone should have N-95 masks and air purifiers ready for wildfire season and people with asthma should get their inhalers refilled.

In addition, Howard says physicians should educate their patients about Canada's air quality index and when they should stay inside. She says she'd frequently see people running outside when the index was at eight or nine.

"It's time that we start to look at air pollution as a huge threat."

Peggy Lam

Stay in touch!

Are there issues you'd like us to cover? Questions you want answered? Do you just want to share a kind word? We'd love to hear from you. Email us atwhatonearth@cbc.ca.

Sign up hereto getWhat on Earth?in yourinbox every Thursday.

Editor: Andre Mayer | Logo design: Skdt McNalty