A WARMING PLANET

Better information on greenhouse gas (GHG) emissions and mitigation potential in the agricultural sector is necessary to manage these emissions and identify responses that are consistent with the food security and economic development priorities of countries. Critical activity data (what crops or livestock are managed in what way) are poor or lacking for many agricultural systems, especially in developing countries. In addition, the currently available methods for quantifying emissions and mitigation are often too expensive or complex or not sufficiently user friendly for widespread use.The purpose of this focus issue is to capture the state of the art in quantifying greenhouse gases from agricultural systems, with the goal of better understanding our current capabilities and near-term potential for improvement, with particular attention to quantification issues relevant to smallholders in developing countries. This work is timely in light of international discussions and negotiations around how agriculture should be included in efforts to reduce and adapt to climate change impacts, and considering that significant climate financing to developing countries in post-2012 agreements may be linked to their increased ability to identify and report GHG emissions (Murphy et al 2010, CCAFS 2011, FAO 2011).

The Ecology of Meat

Gaining Acceptance of Novel Plant Breeding Technologies.

Bioenergy from perennial grasses mitigates climate change via displacing fossil fuels and storing atmospheric CO2 belowground as soil carbon. Here, we conduct a critical review to examine whether increasing plant diversity in bioenergy grassland systems can further increase their climate change mitigation potential. We find that compared with highly productive monocultures, diverse mixtures tend to produce as great or greater yields. In particular, there is strong evidence that legume addition improves yield, in some cases equivalent to mineral nitrogen fertilization at 33–150 kg per ha. Plant diversity can also promote soil carbon storage in the long term, reduce soil N2O emissions by 30%–40%, and suppress weed invasion, hence reducing herbicide use. These potential benefits of plant diversity translate to 50%–65% greater life-cycle greenhouse gas savings for biofuels from more diverse grassland biomass grown on degraded soils. In addition, there is growing evidence that plant diversity can accelerate land restoration. Bioenergy from perennial grasses mitigates climate change via displacing fossil fuels and storing atmospheric CO2 belowground as soil carbon. Here, we conduct a critical review to examine whether increasing plant diversity in bioenergy grassland systems can further increase their climate change mitigation potential. We find that compared with highly productive monocultures, diverse mixtures tend to produce as great or greater yields. In particular, there is strong evidence that legume addition improves yield, in some cases equivalent to mineral nitrogen fertilization at 33–150 kg per ha. Plant diversity can also promote soil carbon storage in the long term, reduce soil N2O emissions by 30%–40%, and suppress weed invasion, hence reducing herbicide use. These potential benefits of plant diversity translate to 50%–65% greater life-cycle greenhouse gas savings for biofuels from more diverse grassland biomass grown on degraded soils. In addition, there is growing evidence that plant diversity can accelerate land restoration.

Debate over climate change is nothing new. Scientists have been arguing about whether greenhouse gases released by human activity might change the climate since the late nineteenth century, when Swedish chemist Svante Arrhenius first proposed that industrial emissions might cause global warming.1 Fueled by partisan bickering, this dispute now is more bellicose than ever.

COP27 Climate Change Conference: Urgent action needed for Africa and the world.

COP27 climate change conference: Urgent action needed for Africa and the world.

Millions at risk: defining critical climate change threats and targets

Climate Change and Health: Strengthening the Evidence Base for Policy

COP27 Climate Change Conference: urgent action needed for Africa and the world: Wealthy nations must step up support for Africa and vulnerable countries in addressing past, present and future impacts of climate change.

Equity in human adaptation-related responses: A systematic global review

城市温室气体排放清单编制研究进展

Twenty-first century sea-level rise could exceed IPCC projections for strong-warming futures

Sub-Saharan African (SSA) countries consist of ~200 million livestock owners who utilise marginal rangelands as a feed resource base for their animals. These rangelands offer various resources to the communities and are in-turn vulnerable to climate change related challenges. Currently, information on greenhouse gases (GHG) emission from SSA rangelands is heavily dependent on the generic values generated by the Intergovernmental Panel on Climate Change (IPCC) Tier I trajectories on various aspects of the environment. There is, therefore, a need to identify research gaps between the dynamics and influences of environmental components, highlight their magnitude and potential aggregate contribution towards GHG emission in an SSA context. Rangeland sustainability, weather patterns, soils, plant biodiversity, and current methods used to measure GHG emission from rangelands are influenced by institutional, community, and national policy frameworks. Various intertwined environmental components exist within the SSA rangeland ecosystems and research has not extensively covered such interactions. It is crucial to generate a database that includes information of in-situ trajectories on GHG emission from soil properties, vegetation image maps using remote sensing and geographic information system, plant biodiversity indices, climatology, and animal husbandry aspects.

The objective was to provide a systematic review of the literature on greenhouse gas (GHG) emissions from swine operations, with a meta-analysis that integrates results of independent studies. A total of 53 studies that measured GHG emissions from swine operations were included in the analyses. Results showed that the Intergovernmental Panel on Climate Change (IPCC) approaches were effective in estimating the overall CH4 and N2O emission levels from swine operations, but the variation of the measured emissions is not adequately captured. An overestimation by the IPCC approaches for CH4 emissions was observed for swine buildings with pit systems in European studies and the average percentage relative difference (PRD) between the measured and the IPCC values is -21.1%. The observed CH4 emissions from lagoons were lower than the IPCC estimated values and the average PRD is -33.9%. In North American studies the observed N2O emission factors for swine buildings with pit systems were significantly lower than the IPCC default values whereas in European studies they were significantly greater than the IPCC default values. The measured CH4 and N2O emissions were significantly affected by stage of production (P = 0.05 and <0.01, respectively) and geographic regions (P = 0.04 and 0.02, respectively). The IPCC approaches were effective in simulating the effect of temperature on CH4 emissions from outdoor slurry storage facilities whereas they could overestimate CH4 emissions from lagoons at low temperatures. The CH4 emissions from pits inside swine buildings were not significantly affected by average ambient temperatures. A positive relationship between diet CP content and CH4 emissions was confirmed in the meta-analysis. The obtained knowledge can be helpful in efforts to improve estimation of GHG emissions from swine operations.