Carbon is a universal building block of life—it's in almost every product we make and use, from the cement we walk on to the plastic packaging used for shipping products and the tires on cars and trucks. And while some products are more durable than others, at the end of the product's life cycle, the carbon stored in them is released into our air and oceans as carbon dioxide. Greenhouse gas emissions from the end of this product value chain are a significant and often overlooked part of our contribution to climate change.