Occasionally, in comments on environmental stories and such, you see the old “we’re so small and the Earth is so big, we can’t possibly be to blame” line of argument. Of course, everything on the Earth affects the Earth, and vice versa, because everything interacts with everything else. Therefore, the question is really whether or not we have a significant effect on the whole planet. As a really basic way of assessing this, I’ve been trying to explore the potential consequences of the oil we use by illustrating the volume of oil that is consumed. According to this Wikipedia page, in 2006 the global oil production rate was 84 million barrels (13 million m³) per day. To give this number some meaning, we can imagine spreading this oil over a large area, say the 244,820 km² surface area of the UK. If you do the calculation, this corresponds to a national oil slick 53 microns deep.
This might not sound like much, until you realise that this daily figure corresponds to just under 2cm of oil per year! Furthermore, a little digging reveals that an oil film on water is about 25 angstroms thick. That means that the daily oil production rate corresponds to enough oil to cover the entire 361,132,000 km² surface-area of the world’s oceans in nice shiny film of oil, fourteen times over. Every day.