REVIEW Monitoring of CO 2 exchange and carbon pools in vegetation and soil Rakesh Pandey • Vijay Paul • Vinay Kumar Sehgal • Madan Pal Singh • Kalikinkar Bandyopadhyay Received: 3 July 2012 / Accepted: 12 March 2013 / Published online: 6 August 2013 Ó Indian Society for Plant Physiology 2013 Abstract Global efforts to reduce the emissions require proper monitoring and understanding of the carbon inputs and outputs by the terrestrial ecosystems i.e. vegetation and soil. Photosynthesis and net primary productivity can be used as indicators of carbon exchange and their estimate can be made through traditional approaches as well as other approaches e.g. mechanistic photosynthesis models and the light use efficiency with satellite data. Advancements have taken place for monitoring the CO 2 exchange at different scales viz. leaf, stand-, landscape levels, vertical carbon column- and satellite observations. There are methods to partition the fluxes based on discrimination of isotopes of carbon by terrestrial ecosystem processes. The soil is a vast reservoir of carbon and has a great potential for atmo- spheric carbon sequestration. Monitoring of carbon and fluxes in soil is therefore an essential aspect in the era of changing climate. The root systems are monitored mostly in a destructive manner but many non-destructive methods have also been devised. Similarly, soil carbon estimation with traditional chemical method can be replaced by reflectance spectroscopy for rapid and large area estima- tions. Measurement of soil respiration and its partitioning also helps in verifying the capacity of soil as a net source or net sink. Monitoring of the pools and fluxes therefore uses multi-technique and -disciplinary approaches. Uncertain- ties in the estimates occur due to the multi-factorial effects and have implications on carbon trading. Therefore more effective monitoring and reduction of the uncertainties is needed. Keywords Carbon cycle  Carbon sequestration  Carbon trading  Climate change  Eddy covariance  Net primary productivity  Photosynthesis  Respiration  Soil organic carbon  Satellite remote sensing Introduction The increase in greenhouse gases (GHGs) is primarily responsible for the recent global warming (Henderson- Sellers 2012). Therefore the goal of reducing the emissions as mandated by different international agencies (e.g. IPCC) is now on global priority. Special mechanisms for emission reduction under Kyoto Protocol include joint implementa- tion, clean development mechanism and emission trading. Besides this, nations need to maintain and update the GHG emission inventories and category on land use change and forestry. Among these GHGs, the atmospheric CO 2 accounts for about 60 % of global warming potential and by 2050 its level will increase to nearly 450 lmol mol -1 (Karl et al. 2009; IPCC report 2007). However, monitoring of GHGs is still inadequate in terms of number of sites, large geographic gaps or spatial resolution (Manning 2011) and requires a multi-technique approach Canadell et al. (2000). Moreover, the response of global carbon cycle to climate change is one of the greatest sources of uncertainty (Balantyne et al. 2012). Houghton (2005) also mentioned that estimation of components of the global carbon cycle is still not accurate. Durant et al. (2011) have emphasized the need for enhancement of measurement infrastructure to reduce uncertainty in global carbon balance and estimated R. Pandey (&)  V. Paul  M. P. Singh Division of Plant Physiology, Indian Agricultural Research Institute, New Delhi 110012, India e-mail: rpandey@iari.res.in V. K. Sehgal  K. Bandyopadhyay Division of Agricultural Physics, Indian Agricultural Research Institute, New Delhi 110012, India 123 Ind J Plant Physiol. (April–June 2013) 18(2):98–117 DOI 10.1007/s40502-013-0016-0