The End of La Niña

The La Niña and El Niño cycles are complex ocean patterns that, in their simplest sense, are periods where the Pacific Ocean is, respectively, cooler or warmer relative to average temperatures. The temperature changes in these periods have wide-ranging effects on the climate system, not just altering temperature, but also influencing rainfall patterns across the globe. We are currently in an unusually (though not exceptionally) long La Niña period, which began in 2020. In these periods ocean surface temperatures can be as much as 3–5 °C cooler than normal conditions. Scientists are now detecting obvious signs that La Niña is weakening, and predict that, by the summer of 2023, we will have reversed states and entered an El Niño period.

With a planet already warming from anthropogenic causes, the sudden temperature spike from a warmer El Niño event will have significant effects on the global climate. This is especially worrying when we consider that 2022, a year of heatwaves, droughts, and famine, was in La Niña, ostensibly a cooler year. Some scientists have predicted that, at least temporarily, this warming will push our global average temperature increase above 1.5°C. But we are not even in El Niño yet, merely the decline of La Niña. So what does this look like in (early) 2023, as a preamble for the more extreme period to come?

Europe’s Winter Droughts

If the ‘cooler’ La Niña year of 2022 was a year of harsh summer droughts, then 2023 is a year of winter droughts. Many of the parched rivers of Europe have not been sufficiently replenished over the winter. Rivers like the Po — Italy’s largest — have not recovered from their 2022 lows. Seawater has flooded up estuaries, and farmers have been unable to plough their fields because the parched soil is too hard. Similar conditions exist in France, which suffered an unprecedented 31 winter days without rain. All of Spain has been in official drought since January, and in response has instituted emergency water-conservation laws that, primarily affecting farms, could cost 25,000 jobs this year.

Even nations that have escaped outright drought, such as Germany, Austria, and the UK, have had remarkably dry winters. The UK for example hovers on the edge of drought, and officials say one prolonged period of below-average rainfall or above-average temperature will push it beyond that threshold.

El Niño usually affects Europe by bringing warmer, wetter weather. As a result, experts last year predicted that we would see a winter relief from drought, due to weakening La Niña conditions (which usually signal a drier climate). The promised relief has not arrived. That Europe will get hotter seems a certainty, but the promise of wetter conditions is increasingly unlikely. As always, we should remember climate change does not merely increase the temperature of the climate, but make it unstable and unlikely to respond as we would expect during ‘natural’ climatic variations.

China Breaks Records Every Month

After a bitterly cold January, China then suffered extremely hot conditions for February and March. Bejing experienced its highest-ever winter temperature (22°C) in February, a full 6°C degrees above its previous record. So far, this March has been the hottest on record, causing last year’s droughts to continue in places such as Yunnan and seriously affecting the province’s hydropower capabilities.

Again, the coming El Niño conditions are expected to bring warmer, wetter weather in China. The wetter conditions may bring boosts to a country strained by water shortages, but combined with higher temperatures, much of china will be vulnerable to ‘wet bulb’ heatwaves. These conditions, a potentially lethal combination of heat and humidity, were almost reached during the ‘drier’ La Niña period. If this year continues to get hotter and wetter as would be expected of El Niño conditions, then the danger of wet bulb temperatures becomes increasingly likely.

South Asia Drought and Heatwave

India has suffered its driest and hottest February on record, with unseasonal wildfires sparking across states like Odisha. Some towns, such as Karwar, experienced their hottest days ever (for any month or year). Across the border, the combination of heat and water scarcity is leading to civil unrest in Pakistan. Unlike in Europe and China, El Niño does not bring wetter conditions to South Asia. Instead, it weakens the monsoon rains, and will only exacerbate the water shortages and temperature spikes. This, combined with higher rates of glacial melt in the Himalayas, affects long-term water security in the region. As scarcity grows worse, geopolitical tensions are heightening, and seem unlikely to lessen given coming conditions.

Longest Cyclone on Record

Cyclone Freddy, which has torn across Madagascar and Mozambique, has persisted longer than any recorded tropical storm. It has repeatedly made landfall in both nations, causing hundreds of deaths, displacing thousands, and destroying tens of thousands of homes. What is uniquely worrying about this storm is not just its longevity and repeated landfills, but how many times it has rapidly gotten stronger. These ‘rapid intensification events’ as they are known, mean that the winds have sped up by at least 35 mph in 24 hours. For Cyclone Freddy, this has happened 6 times, reaching top wind speeds of 165mph. El Niño periods increase the surface temperature of the ocean off the coast of east Africa, creating the perfect conditions for more storms like cyclone Freddy.

The Coming El Niño

These are just a few snapshots of a changed climate reacting to the decline of La Niña and the emergence of El Niño. Alongside these, Australia and New Zealand have seen massive flooding, and Antarctica is experiencing its lowest Ice levels on record. El Niño conditions affect different parts of the world in different ways, drying out some and increasing rainfall in others. But even these generalized parameters should be taken with a grain of salt, as an altered climate is one of discontinuity and uncertainty. How natural cycles interact with this anthropogenic change cannot be solidly predicted. What we can expect are more records to be broken, and increasing uncertainty on what ‘normal’ weather even looks like anymore.

That said, the definitive signs of El Niño’s emergence are already appearing off the coast of Peru. Whilst it’s exact regional effects are difficult to predict, what can be said for certain is that it is going to get hotter. Climate change is already driving warming, and combined with the impact of El Niño, there stands a strong chance we will exceed the 1.5°C target. What remains to be seen now is how our societies react, adapt, and plan in a climate system full of extremes and without certainties.

Teaser photo credit: A dry creek bed in Hartz Mountains, Tasmania, Australia.. Photo by Matt Palmer on Unsplash