ABSTRACT
Environmental hazards have many influences, including longer-term processes such as climate. Climate is weather statistics averaged over decades and changes naturally in many ways over decades, centuries, millennia and epochs. Today, human activity releases gases into the atmosphere and destroys ecosystems absorbing these gases. As the concentration of these greenhouse gases rises, the sun’s heat is trapped, raising the Earth’s temperature and changing the climate with impacts on weather. This chapter begins by describing what is meant by climate, climate change, climate variability and anthropogenic global warming (AGW). It then focuses on how weather has changed, and the consequences for environmental hazards, with some parameters becoming more extreme, some becoming less extreme and others changing their characteristics and distributions away from the extremes. Plenty can and should be done to stop the changing environmental hazards from becoming disasters, just as disaster risk reduction is needed even without human-caused and natural climate change. The chapter goes on to consider some of the many other large-scale hazards affecting the Earth, from collisions with space objects to flood basalts, some of which are incredibly rare yet could threaten the extinction of humanity.
