Steelmaking is one of the world's most climate-polluting heavy industries, but there are many new approaches to making "clean" steel to meet the enormous demand for this material.

The polar jet stream and polar vortex are two rings of fast-moving air around the Arctic, which, as the climate warms, may change in ways that cause some places to see more extreme cold spells during winter.

Organic waste creates climate-warming greenhouse gases when it decomposes, but careful management can prevent it from contributing to climate change.