Super El Niño may push an already stressed climate ecosystem across a critical threshold, climate change researcher says

Forecasters are warning that the ongoing El Niño is likely to become supercharged in the coming months and inject potentially unprecedented heat into our already warming world.

El Niño is the warm phase of a multiyear natural climate pattern, but models suggest this year's cycle will be exceptionally intense. Super El Niño conditions could contribute to temperature extremes until next year, but scientists are warning that it may also pose longer-term threats.

Jong-Seong Kug, a professor in the Department of Earth and Environmental Sciences at Seoul National University in South Korea, uses observational data and artificial intelligence to model El Niño events.

Kug has found that super El Niño events can drive sudden, dramatic and even irreversible climate regime shifts. Live Science spoke with Kug to learn more about climate regime shifts and the long-term threats posed by this year's ongoing El Niño.

Jong-Seong Kug

Jong-Seong Kug is a professor in the Department of Earth and Environmental Sciences at Seoul National University in South Korea.

Patrick Pester: Last year, you published a study that found super El Niño events significantly increase the likelihood of potentially irreversible climate regime shifts. With a super El Niño now looking very likely, how concerned should we be?

Jong-Seong Kug: We should be concerned but not alarmist, because our study does not suggest that every super El Niño inevitably causes a climate regime shift. Rather, a super El Niño can push an already-stressed climate ecosystem across a critical threshold. If a system is near a critical threshold, then strong forcing can induce irreversible change.

Current forecasts indicate a very strong El Niño is increasingly likely later this year. We need to watch vulnerable regions closely, particularly those that are already experiencing severe warming, drying, ecosystem degradation or ocean stress.

PP: What kind of climate regime shift do you fear most?

J-S K: I am particularly concerned about the persistent shift in major ecosystems, such as the Amazon rainforest moving toward a much drier and degraded state. You know, a long time ago the Amazon was a savannah area, so we are now approaching this kind of tipping point. Also, in the Amazon, this drying can weaken [or] even reverse the forest's role as a carbon sink.

The Amazon is a carbon sink, but imagine it becomes drier and drier, and there's some die-back of the forest. Now, [carbon] sink becomes source. This could amplify global warming long after an El Niño event.

PP: Is there anything we can do to mitigate the threat of extreme climate and weather events in the coming months?

J-S K: We cannot stop El Niño. But we can greatly reduce its human impact or ecosystem impact. Governments should use precision forecasts to strengthen our heat health plan, water and food management and flood and wildfire preparedness. In the long term, a rapid reduction in greenhouse gas emissions remains essential because every additional degree of warming increases this possibility that an extreme natural event will trigger lasting damage.

PP: Do you think a reduction in greenhouse gas emissions is likely, given where we are now?

J-S K: I don't think so. It's very difficult.

PP: So, where does that leave us?

J-S K: I don't know. There are some additional techniques we may use at a critical point. Have you heard about climate engineering? Like stratospheric aerosol injection [reflecting solar radiation back into space]. If we cannot do anything, then we have to choose that kind of technology. I don't want this kind of situation, but maybe in the near future we have to decide.

There are two kinds of climate engineering. One is carbon mitigation, just direct air capture [taking carbon out of the atmosphere]. That is a safe way. The other is solar energy management. We can deflect more solar energy from the surface.

So, the easiest way is just to inject an aerosol into the stratosphere; then this aerosol reflects solar radiation, and then global temperatures will decrease. It's like a volcano: After a big eruption of a volcano, the global mean temperature drops by about 0.6 degrees [Celsius, or 1 degree Fahrenheit] because there is volcano aerosol [in the atmosphere]. Instead of volcano aerosol, artificially we can inject aerosol into the stratosphere. Then global temperature can easily decrease.

But there are many side effects. Some we already know, but some we don't know. Like climate inequality. If we artificially decrease temperatures, then some countries will have a drought or a flood. And then how will we compensate?

Obviously, if you want some kind of climate mitigation, we need a kind of consensus across the countries.

PP: Is there anything else you'd like to add that we haven't covered?

J-S K: This year, super El Niño is developing in an already exceptionally warm climate. We are already seeing widespread heat waves this year, so we cannot attribute every individual event to this El Niño. But El Niño will intensify toward the end of this year, so it is likely to further increase the risk of extreme events in many regions, so we need to prepare.

Editor's note: This interview has been edited and condensed for clarity.