The human ecology of climate change - Climate Change: Biological and Human Aspects - page 382

density and (3) species' life-history traits such as gestation period and weaning
age. They found that extinction risk exhibited a positive relationship with a species'
body mass. Importantly, they noted that extinction risk increases sharply when a
species' adult body mass exceeds 3 kg. Second, whereas extinction risk in small
species is driven by environmental factors, in larger species it is driven by both
environmental factors and the species' intrinsic traits. Consequently, they conclude,
'the disadvantages of large size are greater than generally recognized, and future loss
of large mammal biodiversity could be far more rapid than expected' (Cardillo et al.,
2005). Interestingly, this is in line with separate work done on mass-extinction events
demonstrating that it is the large species that are most vulnerable in such events
(Hallam, 2004).
Linking such research to the spatial manifestation of climate change is likely to
receive greater attention in the coming years and no doubt will continue to do so as
geographic climate models become more detailed with regards to both climate and
geography. Meanwhile, competition for land for humans as opposed to habitat for
wildlife continues irrespective of climate change, which is a compounding factor.
To practically address this, biological conservation managers are developing eco-
logical networks of habitat with corridors between reserves, small 'stepping stone'
reserves and permeable areas (either low-intensity human use or a landscape with
semi-natural features) through which species can migrate and buffer zones of semi-
natural landscape to protect the key elements. There are now around 250 ecological
networks globally. In 1995, 53 European countries agreed to the establishment of the
Pan-European Ecological Network (PEEN). The European Centre for Nature Con-
servation (ECNC) coordinates this work in collaboration with the Council of Europe
(Parliamentary Office of Science and Technology, 2008).
7.2 Energysupply
Over half of global warming in recent decades is attributable to anthropogenic carbon
dioxide (see Figure 1.2) and the clear majority of this comes from the burning of
fossil fuels (see Chapter 1). Consequently, the fuels we use to supply commercial
energy are central to climate change policies.
7.2.1 Energysupply:thehistoricalcontext
Ultimately nearly all energy on Earth - except for hydrogen (and perhaps theoretically
potential exotic energy such as zero-point energy) - comes from the Sun and other
stars. Most mechanical energy on the Earth arises in one, or a combination, of two
ways: first, from the solar energy driving movement in the atmosphere, wind and
in turn waves, waving tree branches and so forth; second, gravitationally through
Earth-Moon interactions and, of course, motion within the Earth's gravitational field.
Solar energy is also trapped by photosynthesis and stored chemically. Chemically
stored energy may be harnessed by living things through the various trophic levels of
ecosystems or geologically trapped as fossil fuels. Geothermal energy (in no small