Saturday on PBS News Weekend, why this summer's extreme heat is contributing to a nationwide blood shortage. Then, as COVID cases surge, why vaccines will soon be harder to get for uninsured Americans. We look at the future of debt relief for Black farmers after decades of discrimination. Plus, how climate change is threatening centuries of culture and history on Tangier Island, Virginia. PBS News is supported by - https://www.pbs.org/newshour/about/funders