Econometric analyses results revealed that policy support via subsidies and extension services have played an important role in promoting the adoption of irrigation technology. Strikingly, the present irrigation pricing policy has played significant but contradictory roles in promoting the adoption of different types of irrigation technology. Irrigation pricing showed a positive impact on household-based irrigation technology, and a negative impact on community-based irrigation technology.

We present the first last-millennium simulation with the Community Earth System Model (CESM) including an interactive carbon cycle in both ocean and land component. Volcanic eruptions emerge as the strongest forcing factor for the preindustrial climate and carbon cycle. We estimate the climate-carbon-cycle feedback in CESM to be at the lower bounds of empirical estimates (1.3ppm/°C). The time of emergence for interannual global land and ocean carbon uptake rates are 1947 and 1877, respectively.

Our study focused on uncertainties in terrestrial C cycling under newly developed scenarios with CMIP5. This study presents first results for examining relative uncertainties of projected terrestrial C cycling in multiple projection components. Only using our new model inter-comparison project data sets enables us to evaluate various uncertainty sources in projection periods. The information on relative uncertainties is useful for climate science and climate change impact evaluation.

We compared a process-based ecosystem model (LPJ-GUESS) with EC measurements to test whether observed interannual variability (IAV) in carbon and water fluxes can be reproduced because it is important to understand the driving mechanisms of IAV. We show that the model's mechanistic process representation for photosynthesis at low temperatures and during drought could be improved, but other process representations are still lacking in order to fully reproduce the observed IAV.

Emissions due to human activity impact on rainfall. This impact depends on the properties of the gases or particles that are emitted. This paper uses improved understanding of relevant processes to produce a new measure, called the Global Precipitation-change Potential, which allows a direct comparison of the effect of different emissions on global-mean rainfall. Carbon dioxide, in the years following its emission, is shown to be less effective than methane emissions at causing rainfall change.

Aviation impacts on climate via contrails, which are often clearly visible in the sky. Contrail formation requires particular cold/moist atmospheric conditions at aircraft cruise altitudes. Climate change is expected to change these conditions. Using simulations from several climate models we conclude that, by 2100, the probability of contrail formation could decrease from 11 to 7%, mostly due to changing conditions in the tropics. There is no consensus on the likely change in mid-latitudes.

This study using a variable resolution global climate model having high-resolution zooming over the South Asian region indicates that the anthropogenic effects have influenced the recent weakening of the monsoon circulation and decline of precipitation. The simulated increase of surface temperature over the Indian region during the post-1950s is accompanied by a significant decrease of monsoon precipitation and soil moisture. This summer time soil drying is detectable under RCP4.5 scenario.

There appears to be a connection between two climate change indicators: an increase in evaporation over source regions and Arctic ice melting.

A general circulation model with an aquaplanet setup is used to study the impact of changes in the oceanic heat transport (OHT) on the atmospheric circulation. The atmosphere counterbalances the imposed changes in OHT. A stronger OHT leads to a decline in the intensity and a poleward shift of the maxima of both the Hadley and Ferrel cells. The efficiency of the climate machine, the intensity of the Lorenz energy cycle and the material entropy production of the system decline with increased OHT.

This study concludes that integrated analysis of course and fine-scale, inter-annual and intra-annual trends enables a more robust identification of changes in vegetation condition. Seasonal trend analysis was found to be very useful in identifying changes in vegetation condition that could be masked if only inter-annual vegetation trend analysis were performed. The finer-scale intra-annual trend analysis revealed trends that were more linked to human activities.

Numerical climate models forecast the weather well beyond the deterministic limit. In this “macroweather” regime, they are random number generators. Stochastic models can have more realistic noises and can be forced to converge to the real-world climate. Existing stochastic models do not exploit the very long atmospheric and oceanic memories. With skill up to decades, our new ScaLIng Macroweather Model (SLIMM) exploits this to make forecasts more accurate than GCMs.

We investigate why some social groups engage in conflicts over shared natural resources while other groups cooperate over the same issue. Drawing on evidence from the particularly puzzling case of water conflict and cooperation in Israel and Palestine, we show that the discursive construction of identities and situation assessments is a crucial explanatory factor. This finding highlights the relevance of bottom-up discursive conflict transformation.

GCMs and economic models are often coupled for climate scenarios. Here, what is examined is how well a simple non-equilibrium thermodynamic model can represent the multi-decadal growth of global civilization. Initialized with growth trends from the 1950s, the model attains high skill at hindcasting how fast the GDP and energy consumption grew during the 2000s. This opens treating the coupled economy and climate as a physically deterministic response to available flows of energy and matter.

This paper uses observations of global and national energy use to attempt to show that the growth in energy use over the last 160 years can be related to the distribution constraints imposed by the networks that link environmentally derived resources to points of end use. Having accounted for the distribution efficiency of this global-scale network, we speculate that the observed long-run return rate on energy of ~2.4%/yr requires regulated deployment of acquisition and end use efficiencies.

This article first discusses the effects of oil exploration on the vulnerability of pastoral communities to climate change. The effects are found to be ambivalent, but mostly aggravating. Second, the article explores the (potential) effects of oil exploration on local conflict dynamics. Findings suggest a risk of escalating company-community conflicts. These conflicts are mostly driven by unfulfilled community expectations for employment, water and development.

Human and natural forces drive climate change. If we have a model for the climate response to forcing, we can identify distinct fingerprints for each force, and their footprint in the observed global temperature can be determined by statistical analysis. This process is called attribution. This work examines the effect delays (long-range memory) in the climate response have on the magnitude of the various footprints. The magnitude of the human footprint turns out to be only weakly affected.

Estimates for land use change CO2 emissions (eLUC) rely on different approaches, implying conceptual differences of what eLUC represents. We use an Earth System Model and quantify differences between two commonly applied methods to be ~20% for historical eLUC but increasing under a future scenario. We decompose eLUC into component fluxes, quantify them, and discuss best practices for global carbon budget accountings and model-data intercomparisons relying on different methods to estimate eLUC.

Croplands are vital ecosystems for human well-being. Properly managed they can supply food, store carbon and even sequester carbon from the atmosphere. Conversely, if poorly managed, croplands can be a source of nitrogen to inland and coastal waters, causing algal blooms, and a source of carbon dioxide to the atmosphere, accentuating climate change. Here we studied cropland management types for their potential to store carbon and minimize nitrogen losses while maintaining crop yields.

A major link between climate and humans in northern Africa, and the Sahel in particular, is land use. We assess possible feedbacks between the type of land use and harvest intensity and climate by analysing a series of idealized GCM experiments using the MPI-ESM. Our study suggests marginal feedback between land use changes and climate changes triggered by strong greenhouse gas emissions.