How does climate change affect El Niño?

ENSO has two regimes: a warm-than-cold atmospheric pressure change in eastern equatorial Pacific (EP-ENSO), and a cold-than-warm atmospheric pressure change in the central Pacific (CP-ENSO). Therefore, a warmer sea causes pressure changes that translate into floods on the eastern-Pacific-rim countries and droughts in regions bordering the western Pacific, while a colder sea from an atmospheric anomaly in the central-western equatorial Pacific has repercussions in North America, south Asia, Australia, the North Atlantic tropical cyclones and is responsible for southern hemisphere storm-track activity. Typically, El Niño events occur every two to seven years and can last for several months.

Scientists have long known that El Niño events are influenced by various natural factors, including ocean temperature, the strength of the trade winds, and the amount of rainfall in different regions of the world. However, research has shown that greenhouse gas emissions from burning fossil fuels are also playing a significant role in the occurrence of El Niño events. So in what ways is El Niño affected by climate change, and more importantly, how does this affect communities?

The most significant effect climate change has on ENSO is temperature variation. As GHG emissions warm the ocean there are more frequent and intense El Niño events. Warmer ocean temperatures can also lead to changes in atmospheric pressure, altering humidity levels in the air and rain patterns, potentially leading to more frequent and intense droughts, floods and other extreme weather events.

All of these shifts in water temperature and atmospheric pressure have far-reaching ecological impacts, , particularly in marine ecosystems, where the warming of ocean temperatures can alter ocean chemistry with devastating effects to sealife with long-term consequences for the health of our planet’s oceans and the communities that depend on them for food and livelihood.

From climate-change modelling, impact analysis, and risk and vulnerability assessments to adaptation and mitigation planning, GHD provides a range of services to help your communities become resilient to the impacts of climate change. Our experts collaborate with you to assess and anticipate the strategic risks and opportunities associated with the long-term effects of climate change. In showcasing our commitment to a more sustainable future, we received two business awards from the Climate Change Business Council Journal: IT: Zero Emission Vehicles and Industry Leadership: Economics of Climate Change.

Articles referenced

^{Geng et al. 2022, ‘Emergence of climate change in the tropical Pacific’, In Natural Climate Change, retrieved May 17, 2023, from https://www.nature.com/articles/s41558-022-01301-z}

^{Geng et al. 2022, ‘Emergence of changing Central-Pacific and Eastern-Pacific El Niño-Southern Oscillation in a warming climate’, In Nature Communications, retrieved May 17, 2023, from https://www.nature.com/articles/s41467-022-33930-5}