Mauna Loa Eruption Threatens a Famous Climate Record
Atop the Mauna Loa volcano on the Big Island of Hawaii, a little more than two miles above sea level, a 124-foot aluminum tower has been collecting carbon dioxide measurements nearly every hour, every day, for over 60 years.
That stopped on Sunday night, when Mauna Loa erupted and the flow of lava cut off power to the monitoring lab there. On Thursday, lava was still moving downhill from the volcano, overtaking roads, but posing few risks to nearby communities.
It was a rare interruption in the data collection that has produced the world’s longest running continuous record of the rising levels of heat-trapping carbon dioxide in the atmosphere.
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The Keeling Curve
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Measurements of carbon dioxide concentrations in the atmosphere from the Mauna Loa Observatory, in parts per million CO2.
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The last volcanic eruption paused data collection for a month.
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One of the longest gaps in the record was due to budgetary cuts.
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Zig-zags in the curve reflect seasonal cycles in the Northern Hemisphere that repeat each year.
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The Keeling Curve
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Measurements of carbon dioxide concentrations in the atmosphere from the Mauna Loa Observatory, in parts per million CO2.
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The last volcanic eruption paused data collection for a month.
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One of the longest gaps in the record was due to budgetary cuts.
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Zig-zags in the curve reflect seasonal cycles in the Northern Hemisphere that repeat each year.
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1960
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The Keeling Curve
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Measurements of carbon dioxide concentrations in the atmosphere from the Mauna Loa Observatory, in parts per million CO2.
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The last volcanic eruption paused data collection for a month.
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Zig-zags in the curve reflect seasonal cycles in the Northern Hemisphere that repeat each year.
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1960
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The record, named the Keeling Curve after the geochemist Charles David Keeling who started the monitoring project in 1958, reveals a saw-toothed line that ticks continually upward over time. That pattern is considered by many scientists to be the most important evidence that the climate is changing because of human activity.
“I think it’s very true that this record has shaped entire careers,” said Dr. Keeling’s son, Ralph.
Before the work of the elder Dr. Keeling, many scientists believed that the oceans and forests would absorb the excess carbon dioxide emitted from the burning of fossil fuels.
The Keeling Curve, over time, disproved that idea. It began to reveal just how much carbon dioxide the land and the oceans were capable of absorbing, said Maureen E. Raymo, director of the Lamont-Doherty Earth Observatory at Columbia University and co-founding dean of the Columbia Climate School.
The carbon dioxide accumulating in the atmosphere is about half of the amount humans emit through burning fossil fuels; a quarter is absorbed by oceans and another quarter is absorbed by forests and stored in ecosystems on land.
Over the past six decades, the measurements have paused only a few times: for three months in 1964 because of federal budget cuts and for a little more than a month in 1984 when the volcano last erupted and cut off power.
This time, it will take at least a few months, maybe longer, to get all of the equipment up-and-running again, said Dr. Ralph Keeling, who took on the monitoring after his father’s death in 2005.
In the meantime, officials are contemplating flying in a generator via helicopter to the Mauna Loa observatory, which is operated by the National Oceanic and Atmospheric Administration. NOAA runs a second carbon dioxide monitoring program there that was also disrupted by the power outage.
ISLAND OF HAWAI‘I
Mauna Loa
Observatory
Lava flow
Mauna Loa
volcano
Eruption began at
Moku‘āweoweo caldera
Honolulu
Hawai‘i
Hawaiian Islands
Area of
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Honolulu
Hawai‘i
Hawaiian Islands
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ISLAND OF
HAWAI‘I
Mauna Loa
Observatory
Lava flow
Mauna Loa
volcano
Eruption began at
Moku‘āweoweo caldera
There are hundreds of other monitoring stations across the world, including more than 70 operated by NOAA, so global recordkeeping will go on. But none hold quite the same symbolism as Mauna Loa, which is home to the first and most frequently cited data.
In the late 1950s, the elder Dr. Keeling developed the first technique for making accurate measurements of carbon dioxide in the atmosphere.
His first Mauna Loa measurements, conducted as part of the Scripps Institution of Oceanography program, recorded an average carbon dioxide concentration of 313 parts per million, meaning that for every one million air particles, 313 of them are carbon dioxide molecules.
Now, levels have peaked around 421 parts per million, the greatest concentration in at least 4 million years. Last year, carbon dioxide emissions totaled 36.3 billion tons, the highest level in history.
Without drastic reductions in greenhouse gas emissions, the planet is on track to warm by an average of 2.1 to 2.9 degrees Celsius, compared with preindustrial levels, by 2100, according to a recent report issued by the United Nations.
That is far higher than the aspirational goal that governments endorsed in the landmark 2015 Paris climate agreement, and it crosses the threshold beyond which scientists say the risk of climate catastrophes increases significantly.
While the Keeling Curve reveals a clear upward trend, it also shows a pattern of zigging and zagging that is almost rhythmic, reflecting seasonal cycles in the Northern Hemisphere that repeat each year. Many scientists like to say that it shows the Earth “breathing.”
During the northern wintertime, the Earth “exhales” carbon dioxide, as vegetation decays and plants reduce photosynthesis, said Colm Sweeney, the associate director of NOAA’s global monitoring lab. When spring comes and vegetation returns, plants and phytoplankton in the ocean begin taking in more carbon dioxide.
The amplitude of that zigzag, or the difference between the highs and the lows of the seasonal swings, is also becoming larger. It is possibly a sign that the growing season in the Northern Hemisphere is beginning earlier in the year as warmer temperatures melt snow and trees grow leaves, Dr. Sweeney said, essentially “spinning the wheel faster.”
The Keeling Curve is largely a triumph of the two Dr. Keelings and a commitment to the painstaking precision required to create a record that could withstand scrutiny. His father examined measurements closely, fussing over every last digit, Dr. Keeling said. Colleagues also described the elder Keeling as a “stickler for every detail.”
He wanted to find the perfect spot to do the monitoring, and chose Mauna Loa because of its remote location, away from both carbon dioxide sources like dense population centers or roads, and carbon sinks like areas of heavy vegetation.
Even now, when scientists want to test new carbon dioxide monitoring equipment, “they go to Mauna Loa,” Dr. Sweeney said.
The technology has evolved to become even more precise over time. Over the last decade and a half, “we’ve increased the degree to which we can see subtleties in the record by almost an order of magnitude,” Dr. Sweeney said. These subtleties amount to tiny, but significant, differences, because researchers are concerned with changes in carbon dioxide levels as small as one part in four thousand.
The Keeling Curve presents “a simple message, and that simple message has stayed true,” Dr. Ralph Keeling said.
Though, he hopes for the day that the curve will start to look different — to bend, flatten and even begin to turn downward, indicating a decrease and eventual end to the carbon dioxide emissions that humans are rapidly pumping into the air.