Good Business eMails: El Niño's fiery side

Air quality is abysmal in the Pacific Northwest today as wildfires rage. Fires in the Spokane, Washington, area torched hundreds of structures in the past few days and forced evacuations for tens of thousands of people. You’ll read more on wildfires from Andrew below.

Also, we have a truly special celebrity interview available in the CNN Weather app today! Sesame Street’s Grover visited our NYC office to talk about how he faced extreme weather in a newly released special. Spoiler alert: He was very brave.

— Mary Gilbert, meteorologist. (You may notice I’m not Angela, your usual guide. She’s taking some well-deserved time off this week and I’ll be subbing in!)

How an already warming world is changing the risks from El Niño

By Andrew Freedman, CNN

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Tim Hansen inspects the remains of a home burned in the Old Trails Fire in Spokane, Washington, on August 3, 2026.

Wildfires began to make their destructive run through neighborhoods in Spokane, Washington on Saturday, eventually burning more than 700 structures in the city and sending about 65,000 people fleeing. Those fires, which are still threatening the area, are the result of long-term drought combined with dangerous fire weather conditions over the weekend that made flames more likely to spread.

Studies have shown that human-caused climate change is making fire weather days more frequent and increasing the size of the annual burned area in the western US while land-use change puts more people and property in the path of the blaze.

There isn’t a clear link between the intensifying Super El Niño in the tropical Pacific Ocean and the wildfires in Washington State, but one can expect to hear a lot more about wildfires on a global scale as the El Niño strengthens and peaks through the coming fall and winter.

This is because El Niño is closely tied to drought conditions in Indonesia, Malaysia and Singapore, a large swath of Australia and northern Brazil, among other areas. In these locations, the effects of El Niño are combining with those same climate change and land-use patterns that affect the Pacific Northwest to make a bad situation even worse.

During the most recent Super El Niño in 2015 and 2016, vast amounts of land burned in Indonesia, largely due to human causes as people lit fires in forested areas to make way for palm oil plantations and other agricultural uses. But the El Niño-linked drought in Indonesia led to far more fires than is typical for the area and culminated in a regional smoke crisis.

This yielded a thick blanket of dangerous smoke covering Indonesia, Singapore, Malaysia and other parts of Southeast Asia. The pollution became a national political issue with pressure put on the government of Indonesia to act to reduce the number and severity of the blazes.

With what is likely to be the strongest El Niño on record underway now, one can anticipate a potential repeat of 2015 to 2016’s wildfire woes (or even worse) occurring in the rainforests of Indonesia in particular.

Australia, too, can have more severe wildfire seasons during El Niño years due to much drier than average conditions brought on by the warming of the central and eastern tropical Pacific Ocean, and ensuing changes in weather patterns.

The ongoing El Niño is a natural climate cycle that is taking place against a backdrop of a rapidly warming world due to fossil fuel pollution. As it turns out, human-caused climate change affects the El Niño so much that the natural cycle appears to be more intense than it really is if one measures it without factoring in the long-term warming that has taken place throughout the tropical Pacific.

Hot, hotter … hottest?

Whether El Niño sets a record for its intensity may depend on how one measures it. The National Oceanic and Atmospheric Administration and other climate monitoring agencies around the world recently switched to a new measuring index to incorporate the long-term warming trend seen throughout the waters of the tropical Pacific Ocean. This warming is associated with human-caused global warming.

This index is known as the Relative Oceanic Niño Index, or RONI for short. It compares the temperature anomalies in the El Niño region to the mean temperatures of the tropical Pacific Ocean overall.

So far, the RONI has been running a bit cooler than the previous index, known as the Oceanic Niño Index, or ONI, which does not take the effects of human-caused global warming into account. Instead, the ONI just looks at the temperature departures from average in a benchmark region of the tropical Pacific. This may make it more likely that this El Niño will set an intensity record using the ONI rather than RONI, although the latter has other advantages.

“The two indices are similar, but the relative one has been slightly better for predicting impacts, and that’s a reason why NOAA and others made the switch,” said Columbia University atmospheric scientist Michael Tippett. In other words, the RONI better captures the impacts that El Niño will have on global weather patterns.

The ongoing El Niño is virtually certain to reach the upper echelon of historical events whether its intensity is measured using the new RONI scale or the older method. However, the older method is running hotter and has a higher likelihood of setting a record, Tippett and other experts told me.