As expected, the amount of additional carbon dioxide being added to the Earth's atmosphere that is attributable to Indonesia's 2015 El Niño-influenced wildfires has finally dropped down to pre-wildfire levels. In a very real sense, that means that the smoke from Indonesia's 2015 wildfires has finally cleared!

The additional carbon dioxide contributed to the Earth's air from the Indonesia's 2015 wildfires generally followed the same trajectory as did the much larger Indonesian wildfires of 1997. From the time the wildfires burst out of control in June 2015, it took about 10 months for the year-over-year change in atmospheric CO₂ concentrations measured at the Mauna Loa Observatory to peak before taking 12 months to drop down to levels consistent with their pre-wildfire event levels.

The dissipation of that additional carbon dioxide contribution to the atmosphere isn't the only noteworthy change for the Earth's climate that has taken place over the same period of time. Investor's Business Daily's editors presented an interesting snippet of news indicating that the world's temperatures followed a similar pattern:

... recently, alarms were sounded over the rise in 2015 and 2016 of global temperatures, even though the rise was a result of a temporary phenomenon — the "El Niño" effect of warming seawaters in the Pacific that create higher temperatures and weather disruptions around the world.

As Christopher Booker of the Sunday Telegraph in Britain noted this week, after being repeatedly warned about 2016 being "the hottest year on record," we now have arrived at this: "In recent months global temperatures have plummeted by more than 0.6 degrees: just as happened 17 years ago after a similarly strong El Niño."

What makes this especially interesting is that it would appear that the same mechanisms that account for the accumulation and dissipation of additional carbon dioxide in the Earth's atmosphere from Indonesian wildfires would also seem to apply for the transfer of excess heat from a strong El Niño effect in the Pacific Ocean to the rest of the planet. Beyond that, we also have a potential explanation to an observation that surprised us regarding the correlation between El Niño events and trends in the rate at which carbon dioxide levels change in the Earth's atmosphere.

The chart provides about as simple of a check for correlation as can be made. In quickly scanning it, we quickly would appear to see that El Niño events are indeed correlated rising concentrations of atmospheric carbon dioxide levels.

But that's looking for what we expect to see (a.k.a. confirmation bias). When we actually counted the number of red vertical bands representing El Niño periods, we actually find that there is an equal number of periods where the rate at which CO₂ accumulates in the air was rising and periods where the rate at which CO₂ accumulates in the air was falling.

That was a surprising result to us. Looking next at La Niña periods, we see these events are actually correlated with transitions between rising and falling rates of CO₂ increases in the Earth's atmosphere. Or more accurately, rising-then-falling rates, and also falling-then-rising rates.

By contrast, El Niño periods tend to occur during periods where the rate at which the concentration of carbon dioxide is increasing in the Earth's atmosphere is either rising or falling - sometimes they occur during periods of transition, but more often than not, they appear to be an either rising or falling proposition.

What we observed during the 2015 Indonesian wildfire event provides a potential explanation for why there doesn't seem to be much of a clear correlation between changing CO₂ levels and El Niño events - the incidence of large wildfires in Indonesia is coincidental to El Niño periods. In other words, you can have El Niño events without necessarily having the massive carbon dioxide-releasing, Indonesian peat-fueled wildfire events to accompany them. We could easily have seen the impact on global temperatures without the emission of any additional carbon dioxide over the past two years.

Another important observation is that the local temperature increases in the Pacific Ocean associated with the 2015 El Niño preceded the Indonesian wildfires that fostered the additional carbon dioxide emissions into the air, where the mechanisms that ultimately transfered the additional heat from the Pacific Ocean across the world were simultaneously distributing the additional CO₂ from Indonesia's 2015 wildfires across the planet as well, where the prior establishment of the El Niño effect helped create the dry conditions that made it possible for the 2015 Indonesian wildfires to have such a global reach.

The last piece of the puzzle is why does the incidence of wildfires in Indonesia have such a large impact on the rate at which carbon dioxide levels change in the planet's atmosphere. The Center for International Forestry Research provides a detailed explanation for how they start and why they last so long compared to other regions of the world that have also experienced large wildfires:

How fires start in Indonesia and why they continue

• Fires in peatland are extremely difficult to put out, often smoldering for days or weeks, threatening to reignite the landscape. Only the heavy downpours of the wet season can truly extinguish them.
• Peat is a mixture of soil and partly decayed vegetation, formed in the wetlands that line the coasts of the Indonesian archipelago.
• Deforestation exposes the peat beneath the trees and together with drainage, dries the material. Clearing and repeated burning also encourage the growth of ferns and shrubs that are themselves more fire-prone.
• Fire is a cheap and easy way for smallholder farmers and large companies to clear land for crops such as oil palm.
• Traditionally, local farmers use slash-and-burn techniques to open up small patches of rainforest for crops and livestock.
• Large-scale developments contribute to expanding use of fires by communities as developments attract migrants and improve access to previous remote areas.
• Weak governance and poor land planning then allow land speculators and other investors to move in.
• Unclear or unenforced land tenure sets the stage for conflict between local smallholders, migrants, government agencies, communities and corporations. Fire is often used to stake claims.
• Although satellite observations show that about 1 in 5 fires start inside of oil palm concessions, recent research by CIFOR suggests the story is more complicated, as local communities also occupy land inside concessions, and fires ignited outside can spread into concessions.
• Indonesia’s palm oil industry is driven by global demand and investment by Malaysian and Singaporean companies, among others. In 2014, Indonesia supplied about 52 percent of the world’s palm oil, which is used in a wide range of products: from potato chips to cosmetics to cooking oil to toothpaste.
• Palm oil is a major spur of economic growth in Indonesia and the region. Together, about 11 million hectares of oil palm plantations produce 33 million tons of oil, generating US$ 21 billion in 2014.

In 2017, the volume of Indonesia's palm oil exports were 42% greater than they were the year before, when the still smoldering 2015 wildfires had negatively impacted that year's production. As that crop grows in economic importance, Indonesia's palm oil producers and its global consumers will have increasing incentives to avoid wildfire damage to its future export crops.

Data Sources

National Oceanographic and Atmospheric Administration. Earth System Research Laboratory. Mauna Loa Observatory CO2 Data. [File Transfer Protocol Text File]. Accessed 5 May 2017.

Previously on Political Calculations

• Global CO2 and Indonesia on Fire
• El Niño, La Niña and Atmospheric Carbon Dioxide
• The Contribution of Wildfires to Atmospheric CO2
• Fossil Fuels Versus Forest Fires in Atmospheric CO2
• The Growing Level of Atmospheric Carbon Dioxide
• Falling Growth Rate for Atmospheric CO2