Carbon Dioxide | Global Temperatures

Atmospheric carbon dioxide CO2 has been monitored at Mauna Loa Observatory since 1958. Many other sites world-wide have been monitoring CO2. They all see the same increasing trend. Click on the graph to examine an interactive version which allows you to zoom in on any section. The blue line is the trend of the data. The varying red line is the monthly plot of values. The red line rises and falls with changes in the growing season primarily in the northern hemisphere. Summer months allow plants to use the CO2 to decrease it as they make O2 using photosynthesis. Winter months produce a rise in CO2 due to decomposition. Close inspection of daily records also shows the CO2 has a cyclical pattern between daytime and nighttime hours. (Not shown on this graph scale.)


Climate scientists also keep track of the global temperature using thousands of land and ocean recording stations world-wide. The trends of those world-wide temperatures also show a rise. When the CO2 and global temperature graphs are overlaid, they show a strong correlation, especially in the most recent decades. This chart comes from the National Climate Assessment published by the U. S. government in 2014. The horizontal line is the long-term average global temperature over land and sea since 1880 to now.

The National Climate Assessment summarizes the impacts of climate change on the United States, now and in the future. A team of more than 300 experts guided by a 60-member Federal Advisory Committee produced the report, which was extensively reviewed by the public and experts, including federal agencies and a panel of the National Academy of Sciences.


National Climate Assessment 2014

Clearly, it is important to know the behavior and concentration of CO2 in the atmosphere if we are to better understand the future impacts of global warming on the planet and the populations on it. The CO2 concentrations are not exactly the same everywhere. Certain regions use up CO2 a little more readily, such as forests. They act as sinks. Regions with less vegetation and large human populations tend to produce a little more CO2 than the average. They act as sources. The oceans also have regions of sinks and sources. None of these deviate much from the global average. But, the trends of CO2 and global temperature are unmistakably linked and rising.

Monitoring of global CO2 has been going on for a long time. Maps are made showing the concentrations such as this one from May 2013. It is from the AIRS instrument on the NASA AQUA satellite. The instrument monitored over 2000 channels of infrared light in the layer of the atmosphere where most weather occurs. It has wide global coverage. Yellow shows high CO2 concentrations. The northern hemisphere shows that as widespread because the growing season in May had not yet begun.

NASA Earth Observatory image by Rob Simmon and Jesse Allen


To gain finer resolution and answer questions about the transport of CO2 horizontally and vertically in the atmosphere, a new satellite, Orbiting Carbon Observatory-2, was launched July 2, 2014. OCO-2 is part of a train of satellites following one another in north-south polar orbit. They are called the A-Train. Coverage of the Earth will be 100%. It will view vertical profiles of the CO2 concentrations with high resolution and give a more detailed look at the sinks and sources of CO2 throughout the seasons for the coming years.

OCO-2 is currently undergoing calibration and validation of the instruments. That involves directing the multiple wavelength light beam down to places that also have ground based instruments in order to gauge the comparison of results. Once the calibration phase is complete, the data can be gathered and distributed to the science community for analysis. On September 5, 2014, OCO-2 passed over Caltech and JPL near Pasadena, CA. This image was released by the NASA Earth Observatory site. Each dot represents a unique measurement of CO2. Their size and color show the value in parts per million. The value over Pasadena by OCO-2 was 402 ppm. The ground based value was 399. This close agreement is very encouraging for the calibration and validation team. World-wide coverage in such high resolution will add tremendously to our knowledge and understanding of the behavior of CO2 in the atmosphere and how it impacts the future of global warming.

NASA Earth Observatory image by Jesse Allen

Scientists at NASA Goddard Space Flight Center released this video of computer modeled CO2 distribution and circulation during the year 2006. Carbon dioxide swirls as winds move it away from its sources. Notice the differences in the northern and southern hemispheres. The growth cycle of plants and trees changes the CO2 with the seasons.

Produced by a computer model called GEOS-5, created by scientists at NASA Goddard’s Global Modeling and Assimilation Office.

The visualization is a product of a simulation called a “Nature Run.” The Nature Run ingests real data on atmospheric conditions and the emission of greenhouse gases and both natural and man-made particulates. The model is then left to run on its own and simulate the natural behavior of the Earth’s atmosphere. This Nature Run simulates January 2006 through December 2006.

While Goddard scientists worked with a “beta” version of the Nature Run internally for several years, they released this updated, improved version to the scientific community for the first time in the fall of 2014.

Thanks to my nephew for pointing me to this video.


15 thoughts on “Carbon Dioxide | Global Temperatures

  1. Fascinating Jim, about the transport of CO2 horizontally and vertically in the atmosphere, and about the increase in winter time.

    • With oil and gas prices low, the push for alternatives is low as well. How short sighted we are. One day the prices will again rise. People will ‘discover’ the need for renewables all over again. We could be in a very solid position by now of smart energy policy if we had chosen a different path decades ago.

  2. I love science but maybe we should move away from confirming what we already know to fixing the problem? Personally, I think it is way past time to move away from measurement to action. Donald F. Hornig’s report to LBJ in 1965 already told everyone everything we needed to know to be aware of this problem. His reported detailed a warmer climate, the melting of Antarctica’s glaciers, a global sea rise and even less obvious phenomenon such as increasing water acidity.

    • Thanks for that link. In looking over the report by the science panel, I noticed some very influential names. You are correct, we have known for a long time what problem we have. As you stated in your blog post linked…”The more I look at history the more astonished I am by how radically this society shifted within my lifetime to being so pro-capitalist and anti-intellectual.” That is a major contributor to our lack of action today.

  3. The upward slope of the CO2 curve is alarming enough, but last Sunday I saw a segment on CBS 60 Minutes telling of something else that is likely to make the situation even worse. Planet Earth is running out of freshwater. The data come from two sources, actual measurements of the water table in selected areas and gravitational measurements by a pair of sophisticated satellites. The two data streams correlate well and confirm that because of population growth and drought in the northern hemisphere, the water table is dropping at an alarming rate. The level under California’s Central Valley, the world’s most fertile growing area, has dropped 200 feet in the past few years, so much that the actual land elevation has dropped about 6 feet. The same thing is happening in other places, most markedly in highly populated areas in India and China.

    This is a classic unstable system. Plant growth is a principal sink for CO2, and when (not if) it declines due to lack of water, CO2 rate of increase will accelerate. The well-drilling business in California is booming, 24/7. Kinda gives new meaning to the GOP mantra, drill, baby, drill, doesn’t it? Here is a link to the CBS 60 Minutes script.

  4. One dictum of statistics is that correlation isn’t causation. If A correlates with B, it’s possible that A causes B, that B causes A, that some third thing C causes both A and B, or that A and B are doing similar things by coincidence alone. How do scientists rule out the possibility in this case that rising temperatures might be causing more carbon dioxide to be produced or retained in the atmosphere?

    • Good question. What I found addresses the possible link between temperature and the resultant release of CO2 from the oceans.

      It comes down to a matter of time lag. Historical records back a few hundred thousand years compare CO2 and temperature from ice core samples, primarily from Antarctica. The end to glacial periods, and the associated warming, tends to come on roughly a 100,000 yr cycle. The ice cores show that CO2 increases from the oceans lag these temperature increases by about 800 years.

      The data today shows no lag between the temperatures of the earth and the CO2 levels. Instead they are in lock-step. It suggests CO2 is forcing the temperatures to increase along the current time line of the recent decades instead of the other way around. There is no evidence that the oceans could respond that quickly to a warmer climate. They are too large and the circulation and mixing are very slow.

      Does that address your question?

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