The increasing concentration of carbon dioxide (CO2) in the atmosphere and the role of human activities in causing this is a much debated and controversial topic. Environmental campaigners and scientists squarely point the blame at our burning of fossil fuels, while some industrialists and politicians question whether we have anything to do with it. In recent years, there has been a growing body of evidence that the increase in CO2 in the atmosphere and its effect on global temperature and climate change is a direct result of anthropogenic activity, leading to increasing acceptance that it’s our fault and that we need to do something about it. Indeed, just last week, at the 2015 United Nations Climate Change Conference in Paris, global leaders agreed to adopt an international accord aimed at transforming the world’s fossil fuel-driven economy within the next few decades and to limit global warming to below 2ºC.
Natural vs. Anthropogenic CO2 Sources
Prior to the industrial revolution, the major sources of CO2 contribution to the atmosphere were occurrences such as large-scale forest fires and volcanic eruptions. Of course, these are still significant contributors today, and their effect on local and global climate conditions needs to be measured together with the effect of anthropogenic sources of CO2 (such as fossil fuel energy generation, industrial process emissions, and vehicle exhaust) to attempt to get a complete picture of what is happening.
Acquiring the most accurate data possible is essential in evaluating the scale of the climate change problem, developing strategies to reduce emissions and testing the effectiveness or otherwise of these strategies. This leads to the obvious question: how can you measure, separate and characterize natural CO2 emissions from human activity? Well, nature has given us a helping hand here in the form of the different isotopes of carbon (12C and 13C) and oxygen (16O, 17O and 18O). The different combination of these isotopes in the CO2 molecule leads to small but detectable differences in the physical properties of each CO2 molecule (e.g. 12C16O2, 13C16O2 and 12C16O18O, also called isotopologues). The proportion of these isotopologues in a given amount of CO2 depends on the source of the carbon and oxygen from which the molecule is derived and from the formation processes, so it is possible to identify where the CO2 detected in a given location has come from.
One way of utilizing these differences in isotopic composition to characterize CO2 is to measure the infrared (IR) absorbance of the different CO2 isotopologues. The Delta Ray Isotope Ratio Infrared Spectrometer (IRIS) scans individual absorption lines in the mid-infrared region to sensitively detect absorbance from each CO2 molecule and from this data, calculate the corresponding δ13C and δ18O values. The terms δ13C and δ18O here mean the relative difference in the 13C/12C and 18O/16O isotope ratios in the CO2 detected relative to the corresponding ratios in known isotopic standard materials.
A big benefit of using infrared spectroscopy for CO2 isotopologue analysis rather than alternative mass spectrometer approaches is the ability to make the instrument portable. This allows CO2 measurements to be made anywhere in the world at the point of emission – something that isn’t practical to do with mass spectrometers, as these instruments require vacuum pumps and are sensitive to being bounced around inside a vehicle.
Like what you are learning?
Delta Ray on the Road
The ability of the Delta Ray IRIS to accurately and precisely measure CO2 isotopologues after being loaded into a truck and transported to multiple locations was put to the test earlier this year, when the instrument was taken on a road trip across Canada. This 5,125-mile coast-to-coast trip through forests, agricultural landscapes, cities, mountains and prairies took in 17 locations, with continuous monitoring of CO2 throughout the whole trip.
Further to the Canadian road trip, we’re excited to announce that the Delta Ray IRIS is being used on the Trail by Fire expedition, which is currently underway in South America. This epic expedition, funded by a bursary from Land Rover and the Royal Geographical Society (with the Institute of British Geographers), is an attempt to quantify the total amount of volatiles released by volcanoes along the Nazca subduction zone, from Peru to the south of Chile. The Delta Ray IRIS has the tasks of continuously measuring ambient, atmospheric CO2 and targeted sampling of volcanic plumes, fumaroles and hydrothermal vents.
It’s worth mentioning at this point that, as well as measuring emissions and studying climate change, the Delta Ray IRIS can be applied to ecological investigation, plant science and carbon sequestration/storage research.
Finally, for those of you with a particular interest in volcanoes, the Delta Ray IRIS will be making a guest appearance early in 2016 at the Volcanic and Magmatic Studies Group (VMSG) meeting in Dublin, from January 6th to 8th. We’ll have the instrument on our booth at the meeting and members of our team will be on hand to answer any questions you might have about it or about the applications for which it can be used.
In the meantime, if you’d like to learn more about how the Delta Ray IRIS instrument can help meet your needs for CO2 analysis, just let us know via the comments box below!
- Webinar: The Power of Stable Isotope Ratio Analysis for a Better Understanding of CO2 in Our Environment
- Delta Ray on the road: Trail by fire expedition on Facebook. Twitter: @trailbyfire
- Video: Land Rover video for Trail by Fire
- Product page: Delta Ray CO2 Isotope Ratio Infrared Spectrometer with URI Connect (for headspace analysis and discrete sampling of CO2)