Climate change is a major threat facing society. The atmospheric burden of greenhouse gases, such as carbon dioxide, methane, and nitrous oxide, is continuously increasing due to anthropogenic emissions, thereby causing global warming, thus reduction of emissions is needed. Measurements of isotopic ratios offer the possibility of discriminating anthropogenic from natural contributions of greenhouse gases. However, harmonised and standardised field calibration and measurements methods are required to support measurements networks such as ICOS and NOAA. This project MetHIR seeks to (1) harmonize field (network) isotope ratio measurements, (2) improve the traceability and (3) realize compatibility of results targeting WMO-GAW compatibility goals.

Empa’s E&I group will focus on two main activities:

1. Establish the analytics for highly sensitive radiocarbon detection in CO₂ from ambient air and perform intercomparison measurements with established AMS laboratories.
2. Develop a measurement method using thermal equilibration to quantify differences in ¹⁵N substitution in nitrogen positions of N₂O and compare to existing reference materials.