The Intergovernmental Panel on Climate Change (IPCC) conducts policyrelevant but not policy-prescriptive assessments of climate science. In this review, we engage with some of the key design features, achievements, and challenges that situate and characterize the IPCC as an intergovernmental organization that is tasked with producing global environmental assessments (GEAs). These include the pr...

[1] The coupled global atmospheric-ocean models used for transient simulations in the IPCC AR4 report differences in the present-day shortwave forcing of more than 2 W/m. We show here that about 1.3 W/m of this spread could be explained by the different methods used to calculate cloud droplet number concentration (CDNC) from aerosol mass concentrations. Although we cannot rule out that other fo...

[1] A set of Markov models is developed based on a statistical linearization of 5 coupled ocean‐atmosphere general circulation models used in the Intergovernmental Panel on Climate Changes Fourth Assessment Report (IPCC AR4), and is applied to ensemble prediction of the tropical Indo‐ Pacific sea surface temperature variations. By taking advantage of the long data records of IPCC simulations, t...

Based on numerical models and climate observations over past centuries, the Intergovernmental Panel on Climate Change (IPCC) attributes to human activity most of the warming observed since the mid-20th century. In this context, this paper presents the first major attempt for climate system identification – in the sense of the systems theory – in the hope to significantly reduce the uncertainty ...

According to IPCC, the climate sensitivity in the absence of feedbacks is T = 1 C. The evaluation is based on the Stefan-Boltzmann law. This naive picture is however doubtful. In the present work we have examined the climate sensitivity in the analytic model of radiative transfer and found that the IPCC is incorrect. The precise climate sensitivity is T = 1:4 C. The observed temperature anomaly...

[1] We perform a sensitivity study with the Biogeochemical Elemental Cycling (BEC) ocean model to understand the impact of atmospheric inorganic nitrogen deposition on marine biogeochemistry and air-sea CO2 exchange. Simulations involved examining the response to three different atmospheric inorganic nitrogen deposition scenarios namely, Pre-industrial (22 Tg N/year), 1990s (39 Tg N/year), and ...

Municipal solid waste generation rate is over-riding the population growth rate in all mega-cities in India. Greenhouse gas emission inventory from landfills of Chennai has been generated by measuring the site specific emission factors in conjunction with relevant activity data as well as using the IPCC methodologies for CH4 inventory preparation. In Chennai, emission flux ranged from 1.0 to 23...