To make a plot of CO2 monthly data from the Maona Loa data in 
co2-mlo-monthly-noaa-esrl.xls:

1. Choose the data you want (e.g. what years to grab) in the spreadsheet
- we will use 1960 through 1980 or 21 years of data

2. Copy these data into a text file - we will use 
co2monthly1960to19980.txt as an example

3.  Import these data into Matlab then rename them as an array x

4. To create a single long array with just the monthly data values in matlab do:

a=[ ];
for i=1:21
a=[a x(i,2:13)];
end

then this creates an array a with just the monthly data (252 points)

5. To plot it just do 
plot(a)
title('monthly co2 1966-1980'),pause

6. Now to create an array of yearly averages from this data set along with the years and place it in a new array d

d=[];
for for i=1:21
dd=[x(i,1) mean(x(i,2:13))];
d=[d;dd];
end

so d then contains an array of size 21 x 2

7. To plot this data set and use it to project CO2 at various years 
run co2projection
by setting 
co2datyearly=d