Climate Change Amplifies El Niño’s Strength
As the formidable El Niño phenomenon intensifies, a new study suggests that human-induced climate change is exacerbating these events. El Niños, which cause global temperature spikes and severe weather disruptions, are reportedly becoming more potent, posing significant challenges worldwide.
Recent research published in the journal Science indicates that El Niño events are now over 36% stronger than they were before the industrial revolution, with a marked 16% increase in strength over the past 40 years. This intensification aligns with the ongoing rise in global temperatures attributed to human activities such as fossil fuel combustion. A current El Niño event, forming just months ago, is projected to be the most intense on record, leading to extreme weather phenomena like heatwaves, floods, and droughts that can cause substantial economic damage.
“That’s important because strong El Niños have much stronger impacts on climate hazards and extremes worldwide,” explained Julia Cole, a paleoclimate scientist at the University of Michigan and the study’s lead author. Her research examined El Niño patterns over the last 900 years, revealing a correlation between El Niño’s increasing intensity and the rise in global temperatures.
The Impact of Aggravated El Niño Events
Dalhousie University marine scientist Boris Worm, who was not involved in the study, described El Niño as “the most violent aspect of climate variability worldwide,” with effects ranging from local fisheries collapse to severe droughts and food shortages. Quoting the late climate scientist Wallace Broecker, Worm emphasized, “The climate system is an angry beast, and we are poking it with sticks,” with human emissions being the provocations and El Niño the resulting reactions threatening global safety.
El Niño’s strength is assessed by comparing water temperatures in the central Pacific near the equator over a three-month period. A temperature rise of 0.5 degrees Celsius (0.9 degrees Fahrenheit) above normal classifies it as an El Niño, with 2 degrees Celsius (3.6 degrees Fahrenheit) marking a “very strong” event. Currently, the El Niño temperature stands at 2.7 degrees (4.9 degrees Fahrenheit), with expectations of further increase in the coming months, according to Columbia University’s El Niño tracker.
While scientists have long predicted stronger El Niños as global temperatures rise, observational records covering only 75 years have posed challenges in establishing a clear trend. Historical records and changes in global weather patterns have helped identify past significant El Niño events, like the massive one in 1877.
Coral Fossils: A Window into the Past
To explore historical El Niño events, Cole’s team used coral fossils as indicators of past ocean temperatures. By analyzing the calcium and strontium ratios in coral skeletons, alongside different oxygen isotopes, the researchers obtained two independent readings of the seawater’s conditions. Additional measurements of uranium and thorium dated the coral formations.
The study examined 29 coral fossils from the Galapagos Islands, spanning from the pre-industrial era to modern times, with the oldest dating back to around 1100. Although temperature data over the past 900 years is intermittent, the findings suggest an intensifying pattern similar to the “hockey stick” trend observed in a landmark 1990s study of global temperatures.
Kim Cobb, a coral and climate scientist at Brown University, noted, “It raises the specter of a future where larger El Niño and La Niña events are dialing up the pace and severity of weather and climate extremes.”
Debate Among Scientists
The study’s findings have sparked debate among scientists, with some endorsing its significance while others express skepticism due to conflicting recent observations. Kim Cobb emphasized the value of coral data, stating, “Corals are the gold standard for El Niño reconstruction, and this brings a goldmine of new material to the table.”
Contrarily, University of Pennsylvania climate scientist Michael Mann and University of North Carolina marine scientist John Bruno pointed out discrepancies between coral data and recent Galapagos water temperature observations, which show a decline in El Niño-related variations amid rising greenhouse gas levels.
Despite differing interpretations, all experts agree on the pressing need to address climate change. Julia Cole underscored the urgency, stating, “It’s important to point to this as one more reason why we need to get off fossil fuels.”
Original Story at www.wcvb.com