How and why does climate vary naturally?
Climate varies on many time scales. For example, a wet month may be followed by a dry month, and a mild winter may be followed by a very cold one. There are also variations on longer time scales of decades, centuries and beyond. We know from geological records that on time scales of hundreds of thousands of years climate has swung between glacial ("ice-age") periods interspersed with milder ("inter-glacial") periods.
We know that many of the variations in climate arise naturally from processes in the atmosphere, in response to changes in the ocean, or as a result of other interactions in the "Earth system". One of the best known natural climate variations is the fluctuation of the tropical Pacific Ocean between warm "El Niño" events and cool "La Niña" events. These events have profound impacts on floods and droughts around the world. Another example is the cooling of Earth's climate that follows major volcanic eruptions.
Understanding how and why climate varies naturally is essential for identifying how human activities have affected climate, and for improving climate predictions.
Some examples of NCAS-Climate research:
- Why are some European winters so cold?
- What causes El Niño/La Niña warming/cooling episodes in the tropical Pacific ocean?
- How do changes in the Sun's output affect climate?
- Why does Indian summer monsoon rainfall vary from year to year?