hqcasanova / co2

JSONP service delivering weekly CO2 averages in PPM

co2

PHP5 JSONP service delivering weekly CO2 averages from NOAA in parts per million. All it does is extract the values from the entry in this web feed corresponding to the latest weekly average. The XML file of the feed is fetched only once a day by default to guarantee that the bandwidth party can go on for the folks at ESRL/NOAA. Not that it is a huge file but just in case.

Why bother?

As expected, NOAA does provide a web service for experimental data from its Global Monitoring Laboratory on Mauna Loa (Hawaii). However, it's not granular enough to give you just CO2 concentrations. This service script aims to cater those users that just want those concentrations and tries to do so in a more plug-and-play fashion.

Response object

Being a JSONP service, a callback parameter is expected. For instance, if the service is hosted at http://www.climate.org/co2 a request to http://www.climate.org/co2?callback=process should yield the following response:

process({
  "0":"411.00",
  "1":"408.34",
  "10":"386.81",
  "units":"ppm",
  "date":"2020-09-27T13:00:56+02:00",
  "delta":5.56,
  "all":"Up-to-date weekly average CO2 at Mauna Loa\nWeek starting on September 20, 2020: 411.00 ppm\nWeekly value from 1 year ago: 408.34 ppm\nWeekly value from 10 years ago: 386.81 ppm"
})

What follows is a description of each of the JSON object's properties:

• 0 Latest weekly average
• 1 Daily average approx. 1 year ago
• 10 Daily average approx. 10 years ago
• units Units in which the averages are expressed
• date ISO-8601 date of publication of the averages
• delta Estimated percentage change between historical daily averages (9 years)
• all Human-readable summary of all three averages

Endpoints

Endpoints giving plain text responses are also supported. Using the same sample URL as in the previous section, these would be:

• http://www.climate.org/co2/[0|1|10] Default response is the daily average.
• http://www.climate.org/co2/delta
• http://www.climate.org/co2/all
• http://www.climate.org/co2/help

JSONP client code

function fn (data) {
    //Fiddle with JSON data
}

var script = document.createElement('script');
script.src = 'http://www.climate.org/co2?callback=fn';

document.getElementsByTagName('head')[0].appendChild(script);

Repo files

• cache.xml Sample source XML file retrieved from NOAA.
• help.txt Plain text file with a brief explanation of the service. Used for the help endpoint.
• index.php Script for the CO2 service.