The Big Lagoon area of Shark Bay is a UNESCO World Heritage Site five hundred miles north of Perth on Australia’s west coast. The shallow waters are home to some of the world’s biggest and most diverse seagrass beds, which in turn are habitat and food for a host of marine species. A committee of government officials and scientists is assessing risks from climate change. One concern is repeats of a 2011 episode of extreme heat and rainfall. The combination of high temperatures and turbidity from runoff after the rains caused a substantial die-off of seagrass. Denham, Western Australia, Australia.