In an article in the Lancet, Andy Haines of the London School of Hygiene and Tropical Medicine, and colleagues, write that, 20 years after the Earth Summit and as world leaders prepare to meet at the Rio+20 conference to advance sustainable development, “[i]mplementation of policies that both improve health and promote sustainable development is urgently needed.” They add, “Many of the development goals [resulting from the Earth Summit] have not been achieved partly because social (including health), economic, and environmental priorities have not been addressed in an integrated manner,” and conclude, “Provision for a healthy world population of 10 billion should be possible without undermining of sustainability. However, such provision will need major changes in policies, institutions, governance, and lifestyles on an unprecedented scale” (6/9).