Over the past two decades we’ve become increasingly sensitive to the overuse of plastic and more concerned about its environmental impact – but to what effect? According to the World Wildlife Fund, we’ve actually used more plastic since the year 2000 than in all the decades leading up to that date. And previous estimates for the amount of plastic in our oceans now appear far too conservative. Feel-good campaigns aside, the signs for the future are far from promising. As part of Radio National's The Big 20: Our Century So Far, Future Tense looks at the increasing consumption of plastic.