Question

(5) The annual mean atmospheric CO2 concentrations measured at Mauna Loa Observatory (MLO) in Hawaii from March 1958 through April 1974 have been obtained by C. David Keeling of the Scripps Institution of Oceanography (SIO). a. The following table list the CO2 concentration of the past 22 year from 1998 to 2019. Please compute the 20-year mean CO2 concentration (e.g., 1998-2017). Then compute and plot the CO2 concentration anomalies time series. [20pts] b. Read "IPCC_2013_Report_AR5" report in Blackboard/reading folder) and explain the reason of the increasing CO2 concentration in the atmosphere? Please cite the corresponding paragraph. [10pts] Year 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 CO2 (ppm) Anomalies(ppm) 366.7 368.38 369.55 371.14 373.28 375.8 377.52 379.8 381.9 383.79 385.6 387.43 389.9 391.65 393.85 396.52 398.65 400.83 404.24 406.55 408.52 411.44

I am trying to figure out part a, maybe then I can do b.

Thanks

Answer 1

a. To address the a part I have constructed a table to calculate the anamolies.

First I have calculated the mean of 20 years (1998-2017), which is 385.15 (rounded off to two decimal places).

Then I have calculated anamolies by subtracting each successive years CO2 concentration from the mean (of 20 years.)

Here a negative value shows a negative anamoly i.e. where the CO2 concentration is below the mean(of 20 years).

And a positive value shows a positive anamoly i.e. where the CO2 concentration is above the mean( of 20 years).

Below is a chart showing the anamolies in successive years.

Please note that the calculated mean is 385.15 (ppm) (rounded off to two decimal places)

9.35 Year CO2 (ppm) Anamolies(ppm) 1998 1366.7 -18.45 1999 368.38 -16.77 2000 36955 -15.6 2001 37114 -14.01 2002 373.28 -11.87 2003 375.8 2004 377.52 -7.63 2005 1379.8 -5.35 2006 381.9 -3.25 2007 383.79 -1.36 2008 385.6 0.45 2009 387.43 2.28 2010 3899 4.75 2011 391.65 6.5 2012 393.85 2013 396.52 11.37 2014 398.65 13.5 2015 400.83 15.68 2016 404.24 19.09 2017 406.55 21.4 2018 408.52 23.37 2019 411.46 26.29

After computing the above table we can compute and plot the CO2 concentration anamolies time series.

PLEASE NOTE THAT -

On the Primary Vertical Axis (left) is the absolute concentration of CO2.

On the Secondary Vertical Axis (right) is the anomaly displayed. ( 0 being the mean value. )

On the Horizontal Axis is the year.

CO2 concentration anamolies time series CO2 (ppm) Anamolies (ppm) 340 2014 2015 2016 2017 2018 2019 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 Year CO2 (ppm) Anamolies(ppm)