Measure for Measure

This last week I had been planning to base my second entry around when travel first began to impact the environment on a global scale. While reading, however, it became clear I didn’t really know what I was looking for; I didn’t know what the impacts of travel were. If I was going to look for a golden spike in the geological records, an idea that will be touched on next time, what should I be looking out for? Hence the topic of this week’s entry: what are the global impacts of travel and how can we measures them?

Written in 2002, Gossling’s 'Global environmental consequences of tourism', highlights succinctly 4 ways leisure travel, but also the transportation of humans more generally, has shaped our environment, and the ways we can measure the impacts. Along with the dispersal of diseases, monitored through case loads and mapping, the impacts are: 

1.) Land cover and use changes. According to Gossling, this is the single most of global environmental change. Central to economic growth land cover has been reducing, and land uses have been changing for centuries, and while travel can directly impact this (roads, railways, airports...), it can also have indirect impacts by linking places and promoting urban expansion. Currently the best way to monitor change is through satellite photos and the level of CO2, CH4 and NOx in the atmosphere.

2.) Energy use. Currently the transport sector is responsible for 25% of the world’s energy usage, and 22% of all fossil fuel emissions (IPCC, 2001). Quite clearly therefore the energy use of transport will impact hugely on global warming, and it is through the levels of greenhouse gases we will be able to measure changes.

3.) Extinction of wild species. Human mobility has caused a massive exchange of species, which in turn has affected our ecosystem functioning. While it is possible to measure the rates of extinction, the extent to which they have been caused by travel is more difficult to ascertain.

While 4 impacts have been highlighted here, it is important to remember there are more (this list is by no means exhaustive) and along with all these physical impacts, travel can change people perceptions of the environment and their relationship with it. Just something to think about next time when you chose to take the bus instead of walk.