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| Mauna Loa active volcano, at the back, is one of the largest volcanoes on Earth. |
AN EXCLUSIVE PLACE ON THE GLOBE
“Back in the 1950's, the observatory was a flagship!” Aidan says. We had the chance to meet Aidan Colton who works at the Mauna Loa Observatory. Aidan is the Atmospheric Scientist of the station. Together with 7 colleagues, Aidan “makes sure that the advanced instruments keep running.” He explains: “The station measures the concentration of gases in the atmosphere. The concentrations we measure are considered as a baseline. There are no disturbances here. First, we are on an island in the middle of the Pacific Ocean. Secondly, the observatory stands at 3396 meters, on Mauna Loa volcano: we are far from sources which pollute the air, like big cities or industries.
We met Aidan at the Mauna Loa Observatory offices located in Hilo, on the Big Island of Hawaii. The observatory is part of the US National Oceanic & Atmospheric Administration, NOAA.
We follow simple but thorough methods to accurately measure not only carbon dioxide concentration but also several other gases. Most gases are measured on a weekly or daily basis. Three of them are measured continuously: carbon dioxide (CO2), methane (CH4) and carbon monoxide (CO). The collected data is processed in Boulder, Colorado. It is then released to the public so that scientists can use it for their research.”
A FIRST WHICH BECAME A FAMOUS CURVE
The Mauna Loa Observatory is a special place when it comes to atmospheric science and climate change. It was here that in the 1950’s Charles Keeling defined an “innovative method which provides accurate and consistent measurements”, Aidan says. “He started with CO2 concentrations. And since then, the observatory draws a curve which has become famous in the scientific world. This Keeling curve allows demonstrating that the concentration of CO2 in the atmosphere has increased ever since.”
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| The Keeling curve constitutes the longest record of direct and continuous measurements of CO2 in the atmosphere. Besides the increase, the curve also shows that the concentrations vary throughout seasons. In summer, growing vegetation absorbs the carbon dioxide which is released by decaying vegetation during winter. The black curve represents the seasonally corrected data. ©NOAA |
Mauna Loa Observatory is one of the 6 atmospheric baseline observatories operated by the Global Monitoring Division. The other locations are: Barrow, Alaska; Trinidad Head, California; Summit, Greenland; American Samoa; and South Pole, Antarctica. Boats and planes also take part in measurements over the Pacific Ocean. ©NOAA
MORE IN THE NORTH THAN IN THE SOUTH
Carbon dioxide (CO2) and the other greenhouse gases are warming the planet. The more greenhouse gases are released to the atmosphere, the warmer our planet gets. Aidan explains: “We are all connected; the climate is a worldwide system. Maybe in some places around the world, during some periods, we do not observe an increase in local temperatures, but there is a global warming. The mechanisms are very complex,” like we mentioned in a 2012 article.
Aidan adds: “The atmosphere is reacting to gases we release, to deforestation, to farming practices, to population activities. Note that the concentrations of CO2 are higher in the northern hemisphere than in the southern hemisphere. This is due to the fact that human activity, land masses and vegetation are mainly in the northern hemisphere of the planet.”
Total annual anthropogenic greenhouse gas (GHG) emissions (gigatonne of CO2-equivalent per year, GtCO2-eq/yr) for the period 1970 to 2010 by gases: CO2 from fossil fuel combustion and industrial processes; CO2 from Forestry and Other Land Use (FOLU); methane (CH4); nitrous oxide (N2O); fluorinated gases covered under the Kyoto Protocol (F-gases). ©IPCC
WHEN CAN THE EMISSIONS DECREASE?
When can we imagine our greenhouse gases emissions will decrease? It depends on the transition to a low-carbon society and how quick it can be. European Union emissions have been going down for 10 years. United States CO2 emissions have started to go down, with natural gas and renewables replacing coal in electricity generation. As a consequence of recent actions from the Chinese government, China emissions could decrease from 2025. They have stabilized already; in 2016 they were lower than in 2015. In India and Indonesia, probably the emissions will not start to decrease before 2025.
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| ©NOAA |
Overall, we can foresee that global emissions will go down somewhere between 2025 and 2035. Later, during the second half of the century, human-caused emissions will go down to zero. The concentrations of CO2 in the atmosphere should stabilize, like the global surface temperatures. However, by that time, the climate will have changed a lot.
The data show the Earth average temperature has now risen about 1.1°C above the levels seen before the industrial revolution. The target aimed in the 2015 Paris Agreement is 1,5°C: the global emissions should actually be decreasing already... The transition has started but it must accelerate.
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The case of China In 2016, China’s solar capacity grew an encouraging 81% to 77GW. This is twice the total installed today in the US. Wind power grew 13% to 149GW: more or less a third of wind energy capacity on Earth is located in China. Coal consumption is going to plateau during the next years; when it starts to decrease, then the country's emissions will start to go down.
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