The ocean’s role in setting the mean position of the Inter-Tropical Convergence Zone

Through study of observations and coupled climate simulations, it is argued that the mean position of the Inter-Tropical Convergence Zone (ITCZ) north of the equator is a consequence of a northwards heat transport across the equator by ocean circulation. Observations suggest that the hemispheric net radiative forcing of climate at the top of the atmosphere is almost perfectly symmetric about the equator, and so the total (atmosphere plus ocean) heat transport across the equator is small (order 0.2 PW northwards). Due to the Atlantic ocean’s meridional overturning circulation, however, the ocean carries significantly more heat northwards across the equator (order 0.4 PW) than does the coupled system. There are two primary consequences. First, atmospheric heat transport is southwards across the equator to compensate (0.2 PW southwards), resulting in the ITCZ being displaced north of the equator. Second, the atmosphere, and indeed the ocean, is slightly warmer (by perhaps 2 °C) in the northern hemisphere than in the southern hemisphere. This leads to the northern hemisphere emitting slightly more outgoing longwave radiation than the southern hemisphere by virtue of its relative warmth, supporting the small northward heat transport by the coupled system across the equator. To conclude, the coupled nature of the problem is illustrated through study of atmosphere–ocean–ice simulations in the idealized setting of an aquaplanet, resolving the key processes at work

Engaging Employees in Corporate Social Responsibility Projects—A Case Study from the Lufthansa Group Showcasing Experiences and Lessons Gathered in Kenya, Rwanda, Nigeria and Columbia.

Social responsibility and sustainable development are concepts of growing interest to the corporate sector, including in the so-called developing world. Although the benefits are manifold and typically include mutual learning, innovation, humanitarian engagement, intercultural exchange, new markets, and effective theory-praxis integration that is aligned with the idea of giving back to the community there is a dearth of research studies featuring the practical outworking of actual cases in a comprehensive, analytical and critical manner. To address this gap in the literature the study employs an exploratory methodological approach examining the Impact Week, a Lufthansa Group CSR program aimed at progressing entrepreneurship, innovation, and intercultural exchange that systematically engages employees as part of an internal qualification program. Data from projects in Kenya, Rwanda, Nigeria and Columbia showed long-term local effects both on a program as well as an individual level of analysis. Findings further indicate that engaging employees in CSR practice has the potential of making organizations more meaningful and thus positively impacting organizational culture and attracting new talents. A human centric as opposed to a utilitarian orientation among stakeholders emerged as an important factor for the longevity and sustainability of CSR practice. Results are relevant to stakeholders interested in learning how social responsibility and sustainability may be enhanced in organizational practice

Long-term climate commitments projected with climate - carbon cycle models

Eight earth system models of intermediate complexity (EMICs) are used to project climate change commitments for the recent IPCC Fourth Assessment Report (IPCC AR4). Simulations are run until year 3000 AD and extend substantially further into the future than conceptually similar simulations with Atmosphere-Ocean General Circulation Models (AOGCMs) coupled to carbon cycle models. We investigate (1) the climate change commitment in response to stabilized greenhouse gases and radiative forcing, (2) the climate change commitment in response to earlier CO2 emissions, and (3) emission trajectories for profiles leading to stabilization of atmospheric CO2 and their uncertainties due to carbon cycle processes. Results over the 21st century compare reasonably well with results from AOGCMs and the suite of EMICs proves well suited to complement more complex models. We identify substantial climate change commitments for sea level rise and global mean surface temperature increase after a stabilization of atmospheric greenhouse gases and radiative forcing in year 2100. The additional warming by year 3000 is 0.6 to 1.6 K for the low-CO2 SRES B1 scenario and 1.3 to 2.2 K for the high-CO2 SRES A2 scenario. Correspondingly, the post-2100 thermal expansion commitment is 0.3 to 1.1 m for SRES B1 and 0.5 to 2.2 m for SRES A2. Sea level continues to rise due to thermal expansion for several centuries after CO2 stabilization.In contrast, surface temperature changes slow down after a century. The meridional overturning circulation is weakened in all EMICs, but recovers to nearly initial values in all but one of the models after centuries for the scenarios considered. Emissions during the 21st century continue to impact atmospheric CO2 andclimate even at year 3000. All models consistently find that most of the anthropogenic carbon emissions are eventually taken up by the ocean (49 to 62 %) in year 3000, and that a substantial fraction (15 to 28 %) is still airborne even after carbon emissions have ceased for 900 years. Future stabilization of atmospheric CO2 and climate change requires a substantial reduction of CO2 emissions below present levels in all EMICs. This reduction needs to be substantially larger if carbon cycle - climate feedbacks are accounted for or if terrestrial CO2 fertilization is not operating. We identify large differences among EMICs in both the response to increasing atmospheric CO2 and the response to climate change. This highlights the need for improved representations of carbon cycle processes in these models apart from the sensitivity to climate change. Sensitivity simulations with one single EMIC indicate that the impact of climate sensitivity related uncertainty on projected allowable emissions is substantially smaller than the uncertainty related to different carbon cycle settings