The global phenomenon El Niño – a band of warm seawater stretching from South America to Asia – regularly disrupts global climate processes.
When it occurs, it often causes severe flooding, drought destroys crops, depletes fish stocks, and increases the incidence of tropical diseases. El Niño is expected to return this year.
A new study by Dartmouth researchers, published in the journal Science, suggests that the economic impact of this recurring climate pattern extends well beyond the event itself. This could result in lasting financial consequences that could last for years and result in trillions of dollars in lost income worldwide.
El Niño affects more than just the weather
The Dartmouth study is pioneering work in this area and provides an assessment of the long-term costs of El Niño. The projected losses presented therein far exceed previous estimates.
El Niño is part of the El Niño South Oscillation – a natural variation between warm and cold temperatures in the tropical Pacific. This cycle also includes the cooler La Niña phase.
El Niño events alter global weather patterns, generally leading to a wetter, warmer winter on the US West Coast and a milder Atlantic hurricane season.
How the study was conducted
Over a period of two years, the researchers examined global economic activity in the decades following the significant El Niño events of 1982–83 and 1997–98. They detected a “persistent sign” of slowing economic growth that lasted for more than five years.
These two events resulted in global economic losses of US$4.1 trillion and US$5.7 trillion, respectively, over the following half decade. Most of that burden fell on the world’s poorest tropical countries.
Looking ahead, researchers predict that global economic losses could reach a staggering $84 trillion in the 21st century. This number accounts for the potential increase in El Niño frequency and strength due to climate change.
What the researchers learned
Even if world leaders deliver on their current promises to reduce carbon emissions, those projections stand. For example, they estimate that the upcoming El Niño in 2023 could cost the global economy by as much as $3 trillion by 2029.
Christopher Callahan, the study’s lead author and a PhD student in geography at Dartmouth, shared that this research contributes to an ongoing discussion about society’s resilience in the face of major climate events such as El Niño.
“We can say with certainty that societies and economies are by no means just taking a hit and recovering,” Callahan said, explaining that the negative economic impact of an El Niño event lasts up to 14 years, if not longer could.
“In the tropics and places exposed to El Niño impacts, there is a sustained signature where growth is delayed by at least five years.” He emphasized the need to include these sustained impacts in quantifying financial costs such events into account.
The aim is to determine the economic consequences of climate change
The study’s lead author, Professor Justin Mankin, emphasized the importance of annual climate variability in determining the economic impact of global warming. Although these climate variability are largely independent of global warming, they can either amplify or mitigate its effects.
El Niño, which people refer to as the “trunk of the tree of climate variability,” is the most significant source of annual climate variability. It changes the weather around the world and leaves significant traces in the national economy.
Mankin argues that while world leaders and the public are right to focus on the steady rise in average global temperatures when discussing climate change, they also need to consider El Niño.
“If you estimate the cost of global warming without taking into account El Niño, then you dramatically underestimate the cost of global warming,” Professor Mankin said.
“Our well-being is affected by our global economy, and our global economy is linked to climate.” His research shows that El Niño’s impact on climate variability is incredibly costly, stalling growth for years. This finding has resulted in cost estimates well in excess of previous ones.
Analysis of past El Niño events
According to Mankin and Callahan’s analysis, the 1982-83 and 1997-98 El Niño events caused United States gross domestic product (GDP) to be about 3% lower in 1988 and 2003 than it otherwise would have been. In contrast, the GDP of tropical coastal countries such as Peru and Indonesia was more than 10% lower in the same years.
“The global pattern of El Niño impacts on climate and the prosperity of different countries reflects the unequal distribution of wealth and climate risks — not to mention responsibility for climate change — around the world,” Mankin said. He pointed out that El Niño exacerbates existing inequalities related to climate change, disproportionately hitting those of us who are least resilient and least prepared.
According to Professor Mankin, the ongoing and significant financial implications their research has uncovered suggest that we are currently unadapted to our existing climate.
“Our accounting department dramatically increases the cost estimate for doing nothing. We must both mitigate climate change and invest more in El Niño prediction and adaptation, as these events will only increase the future costs of global warming.”
Concerns about the impact of El Niño in 2023
The 2023 predicted El Niño is expected to occur at a time of record high sea surface temperatures. Callahan pointed out that the last big El Niño in 2016 helped make that year the hottest year on record.
Since then, global warming has only intensified. In addition, the world is emerging from a prolonged La Niña phase, and these two phases can reinforce each other. The National Oceanic and Atmospheric Administration projects an over 80% chance that El Niño will begin in late summer.
“The potential for a really big El Niño is great,” Callahan said. He reckons there is likely to be significant economic damage, potentially slowing economic growth in tropical countries for up to a decade. This could result in trillions of dollars in lost global productivity compared to a world without this El Niño.
More about El Nino
El Niño is a naturally occurring climate pattern that results in changes in water temperature in the central and eastern parts of the Pacific Ocean’s tropical belt. Its full name, El Niño Southern Oscillation (ENSO), refers to the cycle of warm (El Niño) and cool (La Niña) phases that this area is experiencing.
During an El Niño period, sea surface temperatures in the central and eastern Pacific become significantly warmer than usual. This warming affects atmospheric pressure patterns and causes a reversal of usual trade winds.
Normally, these winds blow from east to west, pushing warm water toward the western Pacific (near Asia). During El Niño, however, these winds weaken or even reverse, causing warm water to spread east toward South America.
The effects of El Niño are far-reaching and global. Here are some of its possible effects:
rainfall
Normally dry regions can experience heavy rainfall, which can lead to flooding. On the other hand, areas with a typically humid climate can experience periods of drought. During the El Niño years, for example, countries like Peru and Ecuador often face heavy rains and floods, while droughts can occur in Australia and parts of Southeast Asia.
temperature
El Niño often causes above-average winter temperatures in western and northern Canada and the western and northern United States. At the same time, temperatures in the southeastern United States may be cooler than normal
Agriculture
Changes in rainfall and temperature can significantly affect agricultural productivity. This can lead to food shortages, rising food prices and economic problems, especially in countries that are heavily dependent on agriculture.
fishing
El Niño can disrupt marine ecosystems. The warmer water temperature leads to a decline in nutrients, leading to a reduction in the productivity of the marine food chain. This has a direct impact on the fishing industry, particularly in South American countries where the economy can be significantly affected.
Health
It can also have health effects. Increased rainfall in certain regions can create breeding grounds for mosquitoes and potentially lead to outbreaks of mosquito-borne diseases such as malaria, dengue fever and Zika virus.
wildlife
Changes in ocean temperatures and precipitation can also disrupt wildlife on land and in the sea, affecting species distribution and behavior.
El Niño events typically occur every two to seven years and can last up to a year or sometimes longer. They are part of a natural cycle and have been around for thousands of years. However, scientists are studying how climate change could affect the frequency and severity of El Niño events.
El Niño is followed by a phase called La Niña, which is characterized by below-average sea surface temperatures in the central and eastern Pacific. This phase also has its own global ramifications, often opposite to those of El Niño.
Predicting El Niño events and their intensity is an active area of scientific research. Improved forecasting models can help countries better prepare for potential environmental and socioeconomic impacts.
—-
Check out EarthSnap, a free app by Eric Ralls and Earth.com.
Comments are closed.