دستهها
دسته: تغییر اقلیم
چکیده:
Social unrest may reflect a variety of factors such as poverty, unemployment, and social injustice. Despite the many possible contributing factors, the timing of violent protests in North Africa and the Middle East in 2011 as well as earlier riots in 2008 coincides with large peaks in global food prices. We identify a specific food price threshold above which protests become likely. These observations suggest that protests may reflect not only long-standing political failings of governments, but also the sudden desperate straits of vulnerable populations. If food prices remain high, there is likely to be persistent and increasing global social disruption. Underlying the food price peaks we also find an ongoing trend of increasing prices. We extrapolate these trends and identify a crossing point to the domain of high impacts, even without price peaks, in 2012-2013. This implies that avoiding global food crises and associated social unrest requires rapid and concerted action.
چکیده:
Climate change will have a bigger impact on your family and friends and all of humanity than the Internet has had. Imagine if you knew a quarter-century ago how information technology and the Internet were going to revolutionize so many aspects of life. Imagine how valuable that knowledge would have been to you and your family. It turns out that we have such advanced knowledge of how climate change will play out over the next quarter-century and beyond. The purpose of this book is to provide you that knowledge.
چکیده:
The United Nations Framework Convention on Climate Change (UNFCCC) secretariat has produced this book to highlight the concerns and needs of developing countries in adapting to the effects of climate change. This book outlines the impact of climate change in four developing country regions: Africa, Asia, Latin America and small island developing States; the vulnerability of these regions to future climate change; current adaptation plans, strategies and actions; and future adaptation options and needs.
چکیده:
The time at which the signal of climate change emerges from the noise of natural climate variability (Time of Emergence, ToE) is a key variable for climate predictions and risk assessments. Here we present a methodology for estimating ToE for individual climate models, and use it to make maps of ToE for surface air temperature (SAT) based on the CMIP3 global climate models. Consistent with previous studies we show that the median ToE occurs several decades sooner in low latitudes, particularly in boreal summer, than in midlatitudes. We also show that the median ToE in the Arctic occurs sooner in boreal winter than in boreal summer. A key new aspect of our study is that we quantify the uncertainty in ToE that arises not only from inter-model differences in the magnitude of the climate change signal, but also from large differences in the simulation of natural climate variability. The uncertainty in ToE is at least 30 years in the regions examined, and as much as 60 years in some regions. Alternative emissions scenarios lead to changes in the both the median ToE (by a decade or more) and its uncertainty. The SRES B1 scenario is associated with a very large uncertainty in ToE in some regions. Our findings have important implications for climate modelling and climate policy which we discuss.
چکیده:
This paper analyses the global consequences to crop yields, production, and risk of hunger of linked socio-economic and climate scenarios. Potential impacts of climate change are estimated for climate change scenarios developed from the HadCM3 global climate model under the Intergovernmental Panel on Climate Change Special Report on Emissions Scenarios (SRES) A1FI, A2, B1, and B2. Projected changes in yield are calculated using transfer functions derived from cropmodel simulations with observed climate data and projected climate change scenarios. The basic linked system (BLS) is used to evaluate consequent changes in global cereal production, cereal prices and the number of people at risk from hunger.
چکیده:
The balance of scientific evidence points clearly to the need for all countries to plan credible emissions reduction policies now, if mankind is to avoid substantial risks to future generations. The impact of global warming is already being felt, and future generations face grave risks if activities continue unaltered. Delaying action increases the cost of meeting any temperature or concentration goal, and raises the risks of irreversible impacts as temperature thresholds are exceeded.