No abstract

The majority of African countries are stricken by food shortages and undernourishment, with much of the population lacking reliable access to food supplies and basic dietary requirements. In this paper, we analyze past trends of food production and consumption in Africa, both for the continent as a whole and for 52 individual countries within it. Fluctuations in the self-sufficiency ratio (SSR) are used to characterize the stability of a country's capacity to sustain its own population, and GDP per capita is taken as representative of national purchasing power. Our study shows that Africa's food self-sufficiency is lower today than it was throughout the entire study period. This is probably a result of demographic expansion, leading to a greater increase in food demand than in food production. At the national level, a decrease in SSR mainly occurred in Northern and Southern Africa, and high SSR fluctuations (i.e. low stability) always appeared in conjunction with low SSR levels. Although "low SSR-low GDP" countries face the most serious food insecurity conditions, both "low SSR-high GDP" and "high SSR-low GDP" countries also need attention.

India and China are two similar developing countries with huge populations, rapid economic growth and limited natural resources, therefore facing the massive pressure of ensuring food security. In this paper, we will discuss the food security situations in these two countries by studying the historical changes of food supply-demand balance with the concept of agricultural land requirements for food (LRF) from 1963-2009. LRF of a country is a function of population, per capita consumption/diet, cropping yield and cropping intensity. We have attempted to discuss and compare our results in a framework which links consumption of different groups of food items to diet patterns; then, to the total land requirement for food in a scenario when population is growing rapidly and diet diversification and urbanization due to economic reform impose excessive pressure on food security of both countries. We also elaborate on the role of technology dissemination and critically analyze the achievements and drawbacks of government policies to ensure food self-sufficiency and food security of OPEN ACCESSSustainability 2015, 7 5372 nations. Our results show that the total LRF increases approximately by 42% and 40%, whereas per capita LRF decreases significantly by about 48% and 30% from 1963-2009, for India and China, respectively. Furthermore, our studies reveal that population growth dominates most of the increase in total LRF for India; whereas diet pattern change induced by income growth drives the major increase in LRF for China. Therefore, sustainable management of agricultural land resource is an urgent need both for India and China as there will be demand for more food to meet the diet requirement for the entire population. We also demonstrate the role of India and China in future global food security programs and the challenges to implement the new land reform policies domestically.

Consumption of fossil fuel resources leads to global warming and climate change. Apart from the negative impact of greenhouse gases on the climate, the increasing emission of anthropogenic heat from energy consumption also brings significant impacts on urban ecosystems and the surface energy balance. The objective of this work is to develop a new method of estimating the global anthropogenic heat budget and validate it on the global scale with a high precision and resolution dataset. A statistical algorithm was applied to estimate the annual mean anthropogenic heat (AH-DMSP) from 1992 to 2010 at 1×1 km2 spatial resolution for the entire planet. AH-DMSP was validated for both provincial and city scales, and results indicate that our dataset performs well at both scales. Compared with other global anthropogenic heat datasets, the AH-DMSP has a higher precision and finer spatial distribution. Although there are some limitations, the AH-DMSP could provide reliable, multi-scale anthropogenic heat information, which could be used for further research on regional or global climate change and urban ecosystems.

This study evaluates the performances of three global satellite datasets (Advanced Very High Resolution Radiometer (AVHRR), Moderate Resolution Imaging Spectroradiometer (MODIS) and Satellite pour l' observation de la Terre (SPOT) of the Mongolian Plateau, where in situ observation is insufficient to assess vegetation dynamics on terrestrial systems. We give a comprehensive assessment of the historical changes in vegetation dynamics by using comparative and correlation methods on the three archives using two indices: the growing season's Normalized Difference Vegetation Index (NDVI) and the Start of the Season Index (SOS). The main findings are: (1) MODIS and SPOT have generally better comparability and consistency in the spatial-temporal trends of NDVI and SOS than AVHRR in this area; (2) all the three archives exhibit better consistency in Inner Mongolia than in Mongolia; (3) integration data analysis of AVHRR (1982AVHRR ( -1997 and SPOT (1998SPOT ( -2012 shows that the dynamics of vegetation growth has three distinct Mongolia experiencing a significant greening in vegetation NDVI compared with no obvious changes in Mongolia; (4) the temporal average SOS showed no significant "earlier spring" onset during the past 31 years, on the middle and northern Mongolian Plateau.