More than one person has grumbled, as they put on a jumper, this January “so much for global warming!” Unfortunately, they are wrong. This wet summer actually is another indicator of climate change – albeit a rather more benign one that last year’s tragic bushfires.
We are currently experiencing a La Niña. This weather pattern, which is the opposite of an El Niño event, is the result of changes to water temperatures across the Eastern, Central and Western parts of the Southern Pacific. This is why the full name for the phenomenon is the El Niño Southern Oscillation (ENSO); water temperatures oscillating back and forth. Wherever water is warmer, there will be greater evaporation followed by more rain. If the waters are warmer in the Central and Eastern Pacific, South America receives more rainfall. This happens in an El Nino. During those years, Australia and our northern neighbours tend to receive below average rainfall, leading to drought and increased fire risk. Conversely, in a La Niña, when the waters closer to us are warmer, we will receive above average rainfall. This is the situation we have this year.
The link to climate change is ominous. Though not caused by global climate change, overall temperature rises are likely to make the effects of both El Niño and La Niña more pronounced, and the cycle more frequent. The ENSO is already associated with extreme weather and negative impacts on both people and the environment, being implicated in events as widely separated as snow in California, famine in East Africa and coral bleaching in Queensland. In other words, while we can be grateful for rain rather than fire, the respite may not last long.