Oil spilled from ships or other sources into the marine environment often occurs in close proximity to coastlines, and oil frequently accumulates in coastal habitats. As a consequence, a rich, albeit occasionally controversial, body of literature describes a broad range of effects of spilled oil across several habitats, communities, and species in coastal environments. This statement is not to imply that spilled oil has less of an effect in pelagic marine ecosystems, but rather that marine spills occurring offshore may be less likely to be detected, and associated effects are more difficult to monitor, evaluate, and quantify (Peterson et al., 2012). As a result, we have a much greater awareness of coastal pollution, which speaks to our need to improve our capacities in understanding the ecology of the open oceans. Conservation of coastal ecosystems and assessment of risks associated with oil spills can be facilitated through a better understanding of processes leading to direct and indirect responses of species and systems to oil exposure.
It is also important to recognize that oil spilled from ships represents only ~9% of the nearly 700 000 barrels of petroleum that enter waters of North America annually from anthropogenic sources (NRC, 2003). The immediate effects of large spills can be defined as acute, due to the obvious and dramatic effects that are observed. In contrast, the remaining 625 000 barrels that are released each year can be thought of as chronic non-point pollution, resulting from oil entering the coastal ocean as runoff in a more consistent but much less conspicuous rate. In this chapter, we primarily address the effects of large oil spills that occur near coastlines and consider their potential for both acute and chronic effects on coastal communities. As described below, in some instances, the effects from chronic exposure may meet or exceed the more evident acute effects from large spills. Consequently, although quantifying chronic effects from low exposure rates can be challenging and time-consuming, the results of such efforts provide insights into the understudied effects of chronic non-point oil pollution.
Renewable energy sources – including biomass, geothermal, ocean, solar, and wind energy, as well as hydropower – have a huge potential to provide energy services for the world. The renewable energy resource base is sufficient to meet several times the present world energy demand and potentially even 10 to 100 times this demand. This chapter includes an in-depth examination of technologies to convert these renewable energy sources to energy carriers that can be used to fulfill our energy needs, including their installed capacity, the amount of energy carriers they produced in 2009, the current state of market and technology development, their economic and financial feasibility in 2009 and in the near future, as well as major issues they may face relative to their sustainability or implementation.
Present uses of renewable energy
Since 1990 the energy provided from renewable sources worldwide has risen at an average rate of nearly 2% a year, but in recent years this rate has increased to about 5% annually (see Figure 11.1.) As a result, the global contribution of renewables has increased from about 74 EJ in 2005 to about 89 EJ in 2009 and represents now 17% of global primary energy supply (528 EJ, see Figure 11.2). Most of this renewable energy comes from the traditional use of biomass (about 39 EJ) and larger-scale hydropower (about 30 EJ), while other renewable technologies provided about 20 EJ.
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