Global Impacts of Climate Change

Introduction

In the previous chapter, the basic facts regarding global warming have been presented, summarizing mainly the latest scientific findings reported by the UN’s Intergovernmental Panel on Climate Change (IPCC), particularly in Working Group I’s Fourth Assessment Report on the Physical Science Basis of Climate Change (Forster et al., 2007).

Given these facts, the question is which are and will be their impacts on our planet, particularly on people’s lives, the environment and the prospects for growth and development in different parts of the world. Are and will these effects be felt evenly across the globe? Which parts of the world are and will be suffering most? In which countries growth is and will be affected more adversely? What are and will be the economic implications of climate change and how people’s everyday lives will be affected, for example in terms of income, per capita consumption or access to food or water? How and to what extent the environment is and will be affected and how do and will the ecosystems react to climate change?

These questions are not of theoretical value only. They have to do with the most basic practical needs and expectations of human societies. They also have to do with the future of the natural environment as we have known it, the ecosystems comprising it and our planet as a whole. The basic facts regarding global warming are alarming. So is the analysis of the impacts of the new reality regarding climate and its evolution on the society, economy and environment. As an example, based on epidemiological studies on various diseases associated with the change in temperature, humidity and precipitation in arid and hot regions, empirical models that have been developed to assess human health risk in the Gulf region to predict elevated levels of diseases and mortality rates under different emission scenarios, as developed by the IPCC, indicate increased mortality rates due to cardiovascular and respiratory illnesses, thermal stress, and increased frequency of infectious vector borne diseases (diseases in which the pathogenic microorganism is transmitted from an infected individual to another individual by an arthropoid or other agent, sometimes with other animals serving as intermediary hosts) in the region between 2070 and 2099 (Husain & Chaudhary, 2008). Another example connects climate change and agriculture and food supply (EPA, 2009). Several factors directly connect the former with the latter. Thus, while an increase in average temperature, can lengthen the growing season in regions with a relatively cool spring and fall, it can adversely affect crops in regions where summer heat already limits production. Also it can increase soil evaporation rates and the chances of severe droughts. Changes in rainfall can affect soil erosion rates and soil moisture, both of which are important for crop yields. Increasing atmospheric CO₂ levels can act as a fertilizer and enhance crop growth, which, however may be tempered by other impacts of climate change (e.g., temperature and precipitation changes). Higher levels of ground level ozone, shaped by both emissions and temperature, limit the growth of crops. Finally, changes in the frequency and severity of heat waves, drought, floods and hurricanes, which are anticipated by global climate models but are more difficult to forecast, may also affect adversely agriculture.