It is vital we understand the causes of food waste and find ways to prevent it. So it’s good to see tweets like the Hubbub figure on pumpkins. They help to raise awareness and make the problem something that we can all do something about. And to help start with changes in your own home this season, consider buying pumpkin varieties that will make great meals afterwards and put them to use before they rot—I know a delicious recipe for risotto that can be made from the pumpkin that’s adorned the entryway for a couple weeks. As we approach Halloween, I’m seeing more and more tweets on the subject of pumpkins and what to do with the leftovers. There are loads of great ideas out there, from composting to great recipes to using the seeds to plant your very own pumpkin patch.However, there are also some shocking statistics. I was struck by the estimate made by Hubbub that 15 million pumpkins in the United Kingdom are thrown away after Halloween. That’s enough to make a bowl of pumpkin soup for everyone in Britain. In the United States, where Halloween precedes Thanksgiving, pumpkins big and small will grace doorsteps, entryways and tabletops throughout the month of November.Not all of these pumpkins make for good eating—the giant ones are better for carving, while smaller varieties like sugar pumpkins are the tasty kinds. But the pumpkin season is a timely reminder that finding a purpose for food that otherwise would be thrown out is a strategy that can feed people who are struggling to make ends meet, help nourish a growing global population, and curb environmental problems like climate change, water scarcity and land degradation.I suspect that most people who throw away their pumpkins instead of making soup, pie or other recipes do so because they are unaware of the overall magnitude of food waste. They might not realize that they could help tackle the issue, and they are doubtless very busy and don’t have much time.There are so many reasons to reduce food waste – financial, social and environmental. More than a billion tons of food is wasted every single year. That’s equivalent to one-third of all food produced in the world. Wasting food costs the average family in the UK an average of nearly $1,000 a year, and the average American family of four $1,500. We also know that in total, if food waste were its own country, it would be the third-largest emitter of greenhouse gas emissions after China and the United States.