As I mentioned in Part 1, I taught environmental science in the 1990s and the first decade of the 21st century. Reviewing the textbook used for that course I provide information below that was taught at the time. The purpose of this series on Another Look at Climate Change is to see whether the predictions made at that time are occurring now. Part 3 – What Are Some Possible Effects…\
One question expressed in the 1990s, as it is today, is why we should be concerned about a few degrees change in temperature. Many at the time, and today, did not see the change of a few degrees any different than the change that occurred between the months of May and July. What’s the big deal? The response is that scientists were not looking at temperature changes over a short period of time, but over longer periods – and how rapidly they were changing. In the ancient past, the warming of the planet was over thousands to hundreds of thousands of years. It was now occurring over decades.
The greenhouse effect. Image: NOAA
Climate models at the time were providing information on where food could be grown, how much could be grown, where droughts and flooding were going to increase, and where wildlife and people might have to live. And, due to the rapid change in temperatures, that we were going to have to deal with it during the next century.
In 2003 a U.S. National Academy of Sciences report provided a “worst-case scenario” of climate and ecological changes that may occur. It mentioned that we might reach an irreversible tipping-point and afterwards would not be able to reverse the effects for thousands of years. It described ecosystems collapsing, low-lying cities would flood, vast wildfires in the forests, grasslands drying out from prolonged droughts. As mountain glaciers melt, rivers that bring needed drinking water to many would dry up. There would be pre-mature extinction of up to half of the planet’s species, prolonged heat waves, increased flooding, more destructive storms, and the spread of tropical diseases beyond their current range.
NOTE: Many of these predictions continue to be discussed today – some are occurring.
The following lists were some of the predictions provided at the time. Do you see any that have occurred?
Effects if CO2 levels reach 450 ppm – NOTE: It was stated at that time that this was unavoidable.
Forest fires will worsen.
Prolonged droughts will intensify.
Deserts will spread.
Major heat waves become more common.
Conflicts over water supplies increase.
Modest increases in crop production in temperate regions.
Crop yields fall by 5-10% in tropical Africa.
Coral reefs affected by bleaching.
Many glaciers melt faster and threaten water supplies for millions of people.
Sea levels rise enough to flood lo-lying coastal areas – such as Bangladesh.
More people exposed to malaria.
High risk of extinction for Arctic species – such as the polar bear.
CURRENT UPDATES ON THESE PREDICTIONS…
In 2024 the Western Fire Chiefs Association reported that though the number of annual wildfires has decreased since the 1990s, the area of land destroyed by wildfires has increased. In the 1990s there was an annual average of 3.3 million acres burned by over 78,000 wildfires in the U.S. Since 2000 a little over 70,000 wildfires have burned over 7 million acres a year. This is due to great fuel load due to drier/drought conditions largely caused by climate change.
In 2023 two NASA scientists confirmed that droughts are becoming more frequent.
In 2018 a study reported by the National Science Foundation confirmed that the Sahara Desert has expanded 10% since 1920.
The U.S. EPA reported in 2023 that heat waves in major cities have increased from 2 a year in the 1960s to 6 a year during the 2010s and 2020s.
The University of Southern California reported that conflicts between states over water supply from the Colorado River are occurring. Others indicate that, though nonviolent at this point, conflicts across the planet over water have begun.
Climate change may negatively affect production of corn and wheat by 2030.
Wheat grows well between 15° – 20°C. However, in sub-Sahara Africa temperatures already exceed this. It is believed that by 2030 wheat production will decrease by 10-20% from 1998-2002 yields.
NOAA reported in 2024 that the world is currently going through a fourth coral bleaching event. Heat stressed bleaching has been a problem in both the northern and southern hemisphere.
Recent evidence suggests that ancient glaciers are melting more than a quarter of a mile a day, which is faster than the models predicted.
The annual frequency of high tide flooding in the U.S. has more than doubled since 2000 – and is predicted to triple by 2050.
Although the risk of getting malaria in the U.S. is low, cases are increasing. Particularly in Florida and Texas.
I could not find any reports of Arctic species that have gone extinct, but there are numerous reports of species endangered of it. One report stated that at the current rate of warming, polar bears could be extinct by the end of the century.
OTHER NOTES:
According to a 2005 study, between 1979 and 2002 the area of the earth’s land experiencing severe drought increased from 15% to 30%. The 2007 IPCC report predicted this increase would continue.
The 2021 IPCC report stated the same, the frequency increase will continue.
This “browning” of the earth will enhance other ecological problems such as reduced soil moisture that will impact plant growth rates, impacting their ability to remove CO2, enhancing warming, and causing some bodies of water to dry up and rivers enable to reach the sea.
The light color of snow and ice in the polar regions reflects solar radiation helping to cool the planet. The melting of this snow and ice – which is predicted / and is happening – will increase the absorption of solar radiation increasing warming. A 2006 NOAA report predicted arctic summers with no floating ice by 2040. Other studies suggest this will happen as early as 2013.
According to the 2007 IPPC report the average sea level is very likely (90-99% certainty) to rise 0.6-1.9 feet during this century. In 2022, global average sea level set a record high – 4 inches above the 1993 level… and the 2021 IPPC report stated that we have passed the tipping for sea level rise – it will rise no matter what we do. We are at a point that coastal communities need to begin planning for this. Predictions from that time on the affects of sea level rise include:
Degradation or destruction of at least one third of the world’s coastal estuaries, wetlands, and coral reefs.
Disruption of many of the world’s coastal fisheries.
Flooding of low-lying barrier islands and erosion of gently sloping coastlines.
Flooding of agricultural lowlands and deltas where rice is grown.
Contamination of coastal freshwater aquifers with salt water – salt intrusion.
Submergence of low-lying islands in the Pacific, Caribbean, and Indian Oceans.
Flooding of coastal cities.
It is known that the amount of methane (a major contributor to greenhouse gases) locked in the permafrost is 50-60 times great than the amount released by burning fossil fuels. According to a 2004 study, 10-20% of the Arctic’s permafrost may thaw this century – enhancing warming. A 2024 report stated that 7% of the current permafrost has melted.
Ocean currents move CO2, warm and cold water across the planet regulating the climate. There was concern at the time that the melting of the poles (particularly Greenland) could introduce enough freshwater to alter these currents and impact the climates of northern Europe and northeastern North America. At the time, scientists did not see this as a threat in the near future.
The increase in extreme weather…
Heat waves, droughts, desertification, flash floods from prolonged rain could all happen…
At the time there was disagreement as to whether warming would increase the frequency and intensity of tropical storms and hurricanes. A 2008 study found that since 1950 for every 1°F increase in ocean temperature in the Atlantic, the number of hurricanes and tropical storms would increase by one third. It also showed that the number of hurricanes with wind speeds of 110 mph or greater increased by 45%. NASA stated since 1980 hurricane activity in the North Atlantic has increased but thus far much of this has been from natural climate variation. However, they did point out one study that showed evidence that the rapid intensification of these storms cannot be explained by natural climate variations and could be connected to climate change.
As the planet warmed it was predicted that ecosystems would shift and change. Some tropical species would disperse further north – tropicalization. We have witnessed the expansion of mangroves into the northern Gulf of Mexico. According to the 2007 IPCC report, about 30% of the land-based plants and animals could disappear. A 2019 United Nations article stated that the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services reported that the rate of extinction has accelerated. Warming was also predicted to disrupt biological clocks of migratory species and the Florida Museum of Natural History has already reported this is happening with migrating songbirds. Warming was also predicted to increase the populations of some species of insects and fungi that damage trees.
There were also predictions to the health of humans…
One will be the increased deaths due to heat waves. Others would be increased disease from insects and allergy issues from increased pollen. A 2024 U.S. Environmental Protection Agency report showed that human deaths related to heat waves has increased since 1979.
This snapshot gives us an idea of how well the computer models predicted the impacts of climate change and whether we should pay closer attention to what the current models are saying for the future. The 2021 IPPC report indicated that we have passed the tipping point for sea level rise and are approaching the tipping point for other possible impacts.
There has been talk about climate for a long time. Though many things are beginning to happen there is more our world can do to help reduce the risk of these possible impacts. In Part 4 of this series, we will look at what was suggested a decade ago and how we are doing with those.
References
Miller, G.T., Spoolman, S.E. 2011. Living in the Environment; Concepts, Connections, and Solutions. 16th Edition. Brooks and Cole. Belmont CA. 674 pp.
As I mentioned in Part 1, I taught Environmental Science in the 1990s and the first decade of the 21st century. The information provided below was taught at that time. The purpose of this series on Another Look at Climate Change is to see if the predictions made at that time are occurring.
Over the 4.5 billion years of our planet’s existence the climate has been altered by volcanic eruptions, changes in solar input, continental drift, and impacts by large meteors. Over the past 900,000 years our atmosphere has experienced periods of cooling and warming known as glacial and interglacial periods. We have been fortunate to be in an interglacial period over the last 10,000 years that has allowed humans to exist and grow. For the past 1000 years temperatures have remained relatively stable but in the last 100 years there has been a noticeable increase. This began when humans began to clear the forests and burn fossil fuels.
Our planet has gone through extreme climate change in the past. Photo: NOAA.
Evidence of these temperature changes has come from analysis of radioisotopes, fossils, plankton, ocean sediments, and tiny bubbles in ice cores. Additional evidence has come from pollen found at the bottom of lakes, tree rings, bat dung in caves, and temperature records collected since 1861.
An ice core is being removed by a NOAA scientist. Photo: NOAA
Interestingly we need the greenhouse effect to maintain the temperatures within a range for us to survive. The Swedish scientist Svante Arrhenius first explained this greenhouse effect in 1896. Solar radiation penetrates our atmosphere and warms the surface of the earth. Hot air generated from this surface heating rises but is trapped by a layer gas that includes carbon dioxide, methane, and water vapor. These gases act as a greenhouse allowing light through but trapping the rising heated air. Hence, they are known as greenhouse gases. Without this natural greenhouse layer, the planet would be too cold for us to live here.
The greenhouse effect. Image: NOAA
The industrial revolution began about 300 years ago. The burning of fossil fuels, and loss of photosynthetic trees due to deforestation, resulted in significant increases in these greenhouse gases. According to a 2007 study, if CO2 emissions continue to increase at a rate of 3.3% each year, we will reach CO2 concentrations near 560 parts per million by 2050 and could reach levels near 1,390 ppm by 2100. At the time this was stated, 2011, scientific studies and models suggested we should prevent CO2 from exceeding 450 ppm. Going beyond this we might exceed a tipping point that could trigger climate change impacts for centuries. NOTE: NOAA published in 2023 that the atmospheric CO2 concentration was 419 ppm.
Power plant on one of the panhandle estuaries. Photo: Flickr
In 1988 the United Nations and the World Meteorological Organization established the Intergovernmental Panel on Climate Change (IPPC) to review past climate changes and predict future ones. This network included over 2500 climate experts from 130 countries. In their 2007 report they stated…
It is very likely (90-99% probability) that the lower atmosphere is warming.
Human activities are responsible for this.
Evidence used for these statements include:
Between 1906-2005 the mean global surface temperature had risen 1.3°F. Most of the increase had taken place SINCE 1980.
Annual greenhouse gases emissions from human activity have risen 70% between 1970 and 2005. Average CO2 emissions were higher than they have been in 650,000 years.
Since 1960 Arctic temperatures have risen twice as fast as the rest of the planet.
In some parts of the world glaciers and sea ice were melting, rainfall patterns were changing, and prolonged droughts were on the rise.
During the 20th century sea levels rose between 4-8 inches.
Data in 2011 showed that the melting of ice in the Arctic had increased since the 2007 IPPC report. One scientist, Allan Robock, stated that the ice was melting at a faster rate than their computer models said it would.
What is the scientific consensus about future temperature change?
It is very likely (90-99% probability) that human activities are the cause of the recent increase. Particularly the burning of fossil fuels.
It is very likely (90-99% probability) the earth’s mean surface temperature will increase 3.6-8.1°F between 2005 and 2100. NOTE: Since 2005 the rate of warming has doubled. In one year (2023) the mean temperature of the planet increased 1.44°F – the largest annual increase in 144 years. This was partially due to being an El Nino year.
In 2011 there was the question as to whether the oceans could help absorb CO2 from the atmosphere. At that time the ocean was absorbing between 25-30% of the CO2 emitted by humans. However, the solubility of CO2 in the oceans decreases with increasing water temperatures. As the oceans warm some of the dissolved CO2 would be re-released into the atmosphere and could amplify global warming and climate change. At that time, the oceans had warmed between 0.6-1.2°F during the 20th century. According to a 2007 study the oceans were absorbing less CO2 than they had in the past. NOTE: A 2017 study indicated that mean sea surface temperatures of the oceans have increased 0.22°F since 2000. This is twice as fast as the early models predicted.
The consensus is that the warming predicted by the computer models used at the time is occurring and – in some cases – faster than they thought.
In Part 3 we will look at what they thought some of the possible effects of this warming trend could be and whether any of those predictions have actually happened.
References
Miller, G.T., Spoolman, S.E. 2011. Living in the Environment; Concepts, Connections, and Solutions. 16th Edition. Brooks and Cole. Belmont CA. 674 pp.
Many from the “baby boomer” generation, which includes me, can probably tell you weather patterns have changed since we were kids. Growing up in Pensacola I remember the pattern of a typical summer day. It would be sunny in the morning, when most of us would get out and do our daily activities, whatever those might have been. The land breezes would shift to sea breeze around noon and by mid afternoon there would be a thunderstorm. These storms generally passed quickly and were followed by a sunny, but cooler afternoon with wonderful sunsets. Most summer days were like this. During winter we generally had frost on the ground – at least three days a week. Again, those who grew up with this I am sure have noticed – it has changed.
In the past people would enjoy the beach in the mornings before the daily afternoon thunderstorm. Photo: Rick O’Connor
Our summer days now seem to be periods of several long hot days with little or no rain at all. When rain does come it seems to be intense, it could last all day and may occur for several days in a row. We will go through periods of intense rain followed by days of all most drought conditions. The days seem to be hotter. If you watch the news, we are continually breaking temperature records. The same could be said about rainy days, there have been several “100-year flood” events in the past decade. Hurricanes were once things we dealt with once in a decade, we now seem to be in the “cone of uncertainty” of some storm each season.
In addition to the changes with weather have come changes with coastal plants and animals. Mangroves, snook, and bone fish – all once thought of as “south Florida species” are now appearing along the Florida panhandle. Manatee encounters are increasing and the threat of invasive species – which once was not an issue due to our colder winters – is something we now must look at. It is changing. As we observe these changes, I often get the question – “is this due to climate change?”
Black mangroves growing near St. George Island in Franklin County. Photo: Joshua Hodson.
In the 1990s I taught environmental science at Pensacola State College and AP Environmental Science at Washington High School. Climate change was a topic we covered and discussed the latest science behind the topic. I still have the textbook I taught from and thought it might be interesting to look back at what was being said at the time and whether the predictions given were actually happening. The chapter on climate change began with a case study. It provided the following:
In June of 1991 the active volcano Mount Pinatubo in the Philippines erupted. The eruption released ash and compounds 22 miles up into the atmosphere. Hot gases and ash rolled down the mountain side killing hundreds of people and filling valleys with toxic materials. It destroyed communities and caused hundreds of millions of dollars’ worth of damage. Despite the horrific impact it also provided scientists with an opportunity.
The eruption of Mt. Pinatubo. Photo: NOAA
Climate scientists had been monitoring global warming for a couple of decades at that point and had developed computer models that could predict both the change of climate in the future (if such warming trends continued) and what impacts these changes may have. But unlike the computer models used to predict the course and landfalls of hurricanes, they had no way of testing them. But with the eruption of Mt. Pinatubo, the opportunity was there.
Based on such models, James Hansen, a NASA scientist at the time, predicted the volcanic eruption would first cool the planet 1°F over a 19-month period and then begin to warm. He predicted that by 1995 temperatures would return to normal. His predictions proved correct. The model had passed the test. This case helped convince most scientists and policy makers that climate model projections should be taken seriously.
Hansen’s model, and 18 other climate models, indicated that global temperatures were likely to rise several degrees during the century – mostly due to human actions – and affect global and regional climates and economies.
Over the next few weeks, we will post a series of articles looking at what was discussed decades ago and see whether the weather patterns we are experiencing match the predictions we discussed in class at that time. We will take another look at climate change.
This tree was downed during Hurricane Michael, which made a late-season (October) landfall as a Category 5 hurricane. Photo credit: Carrie Stevenson, UF IFAS Extension
There are a lot of jokes out there about the four seasons in Florida—instead of spring, summer, fall, and winter; we have tourist, mosquito, hurricane, and football seasons. The weather and change in seasons are definitely different in a mostly-subtropical state, although we in north Florida do get our share of cold weather (particularly in January!).
All jokes aside, hurricane season is a real issue in our state. With the official season about to begin (June 1) and running through November 30, hurricanes in the Gulf-Atlantic region are a legitimate concern for fully half the calendar year. According to records kept since the 1850’s, our lovely state has been hit with more than 120 hurricanes, double that of the closest high-frequency target, Texas. Hurricanes can affect areas more than 50 miles inland, meaning there is essentially no place to hide in our long, skinny, peninsular state.
A disaster supply kit contains everything your family might need to survive without power and water for several days. Photo credit: Weather Underground
I point all these things out not to cause anxiety, but to remind readers (and especially new Florida residents) that is it imperative to be prepared for hurricane season. Just like picking up pens, notebooks, and new clothes at the start of the school year, it’s important to prepare for hurricane season by firing up (or purchasing) a generator, creating a disaster kit, and making an evacuation plan.
A summary infographic showing hurricane season probability and numbers of named storms predicted from NOAA’s 2024 Atlantic Hurricane Season Outlook. (Spanish version) (Image credit: NOAA)
Peak season for hurricanes is September. Particularly for those in the far western Panhandle, September 16 seems to be our target—Hurricane Ivan hit us on that date in 2004, and Sally made landfall exactly 16 years later, in 2020. But if the season starts in June, why is September so intense? By late August, the Gulf and Atlantic waters have been absorbing summer temperatures for 3 months. The water is as warm as it will be all year, as ambient air temperatures hit their peak. This warm water is hurricane fuel—it is a source of heat energy that generates power for the storm. Tropical storms will form early and late in the season, but the highest frequency (and often the strongest ones) are mid-August through late September. We are potentially in for a doozy of a season this year, too–NOAA forecasters are predicting a very active season, including up to 25 named storms. According to a recent article from Yale Climate Connections, Gulf waters are hotter this May than any year since oceanographers started measuring it in 1981.
The front right quadrant of a hurricane is the strongest portion of a storm. Photo credit: Weather Nation
If you have lived in a hurricane-prone area, you know you don’t want to be on the front right side of the storm. For example, here in Pensacola, if a storm lands in western Mobile or Gulf Shores, Alabama, the impact will nail us. Meteorologists divide hurricanes up into quadrants around the center eye. Because hurricanes spin counterclockwise but move forward, the right front quadrant will take the biggest hit from the storm. A community 20 miles away but on the opposite side of a hurricane may experience little to no damage.
Flooding and storm surge are the most dangerous aspects of a hurricane. Photo credit: Carrie Stevenson, UF IFAS Extension
Hurricanes bring with them high winds, heavy rains, and storm surge. Of all those concerns, storm surge is the deadliest, accounting for about half the deaths associated with hurricanes in the past 50 years. Many waterfront residents are taken by surprise at the rapid increase in water level due to surge and wait until too late to evacuate. Storm surge is caused by the pressure of the incoming hurricane building up and pushing the surrounding water inland. Storm surge for Hurricane Katrina was 30 feet above normal sea level, causing devastating floods throughout coastal Louisiana and Mississippi. Due to the dangerous nature of storm surge, NOAA and the National Weather Service have begun announcing storm surge warnings along with hurricane and tornado warnings.
You might have seen a floating oyster farm while driving over Garcon Point Bridge or along Scenic Highway. Many people know them for the beautiful, tasty oysters they produce, but those farms have a major ecological benefit that many aren’t aware of. First, the oysters in those cages act as a very efficient water filter, filtering upwards of 30 gallons per day. The floating farms also act as an oasis for other marine creatures, from crustaceans to finfish, and can help increase the biodiversity in the area. Oysters are also great at sequestering carbon into their shells. Today, we will go over these ecological benefits and proper etiquette when maneuvering around the farms to enjoy some of the ecological benefits of the oyster farm.
Florida Pompano Caught Off an Oyster Farm – Thomas Derbes II
Besides being tasty, oysters are very well known for their ability to filter massive amounts of water in a single day. Research has shown rates of up to 50 gallons per day in a laboratory setting, but they filter upwards of 30 gallons per day in the wild. With most oyster farms in the area having more than 500,000 oysters on their farm, that’s more than 15,000,000 gallons of water per day per farm! Oysters can filter out any excess sediments from the water, forming them into small packets and depositing the sediment on the bottom of the bay, keeping the sediments from being re-suspended. This is very beneficial to any bay or estuary as eutrophication (More Here on Eutrophication) has been an issue in almost every bay in the southern United States.
Another benefit to oyster farms is that it is a floating oasis for all types of marine creatures. Blue crabs and stone crabs are a common threat to oysters, and they love to congregate around oyster farms waiting for an easy meal from a dropped oyster or oyster spat on cages. Common bay fish, like the Spotted Seatrout, Sheepshead, and Red Drum, have been known to hang out under the cages consuming smaller finfish and crabs, but some uncommon fish like Tripletail and Florida Pompano also patrol the cages looking for a meal. Because of its ability to hold all types of fish, fishermen love to fish around the oyster farms. Fishing around oyster farms is allowed, but most farmers want the boats to stay on the boundary of the farm and not inside of it. This is due to there being lines under the surface of the water that could potentially damage any lower unit and can cut free a line of cages. Also, it is against state law to be within the boundary of the farm if you are not an authorized harvester of that lease, and I have personally seen FWC enforce those rules. As a seasoned oyster farmer once told me “We know our farm holds fish and it is okay for them to fish the farm, heck put out some blue crab traps around it, but do not mess with the cages and stay outside of the boundary and we can all live in harmony.”
Tripletail Caught Off An Oyster Farm – Brandon Smith
Last but not least is the ability of oysters to sequester carbon and excess nitrogen into their shells and pseudofaeces (aka bio-deposits). Carbon and nitrogen sequestration is a crucial service provided by oysters that helps battle global climate change. Just as they do with excess sediments, they deposit excess carbon and nitrogen into bio-deposits that accumulate on the bottom, keeping them from being re-suspended into the waters. Oyster reefs are currently on the decline around the world, and their decline has “resulted in a forfeiture of several ecosystem services” including carbon and nitrogen sequestration and water filtration. (More Here on Carbon Sequestration)
While oysters might be tasty, we have learned about some of the ecological services oysters provide to an estuarine environment. From water filtration to increasing biodiversity to carbon/nitrogen sequestration, oysters are a major benefit to any estuary and can help fight climate change and eutrophication. Next time you see an oyster farm or reef, give oysters (and farmers) a little appreciation for their hard work in helping make the world a healthier place!
I am sure everyone has noticed how cold this winter has been. We have had multiple days in the 20’s here in the Florida panhandle, even some snow flurries near Pensacola. I was first told this may happen by a Sea Grant colleague of mine who works with oyster farmers. Six months ago, he said the Farmer’s Almanac mentioned this would be a colder than normal winter. A few weeks later a Master Naturalist mentioned that if it was heavy “mast season” (lots of acorns on the ground) it would be a colder winter. We certainly had a heavy mast season in Pensacola this year, acorns were EVERYWHERE. And here we are. As I type this it is 27°F outside.
Though we do not see snow as often as Colorado, the panhandle does see snow from time to time.
Photo: Rick O’Connor
This past week I was at a Sea Grant meeting. We were discussing this cold and another colleague mentioned that it was an El Nino year. That’s right… it is an El Nino year, and many know that the weather does change when this occurs.
I first heard of the El Nino shortly after receiving my bachelor’s degree. I was teaching at Dauphin Island Sea Lab, and we had a video series on oceanography and one episode discussed it. It explained that commercial fishermen in Peru were the first to notice it over a century ago.
Off Peru’s coast is a large ocean current that originates in the Antarctic, flows north towards the equator passing the west coast of South America along the way. The water is cold and full of life. The Andes Mountains also run north-south along the coast. Cold air at the top of the mountains runs down towards the coast and offshore. As it blows offshore, it “pushes” the surface water of the ocean offshore as well. This generates an upwelling current moving from the ocean floor towards the surface, bringing with it nutrients from the sediments below. This nutrient reach seawater, mixing with the highly oxygenated cold water, and the sun at the surface creates the perfect environment for a plankton bloom, and a large bloom she is. This large bloom attracts many plankton feeding organisms, including the commercially sought after anchovies and sardines. This in turn supports the tuna fishery that comes to feed on the small fish. These are some of the most productive fisheries on the planet.
Based on records kept by Peruvian fishermen, every three to seven years the surface waters would warm, and the fish would go away. It was lean times for them. When it did occur, it would do so around Christmas time. So, the fishermen referred to it as the El Nino – “the child”.
Based on the video episode we showed the students, others began to notice warming along the western Pacific and realized it was a not a local event, but a global one. A high school friend of mine does sound for nature films and one of his first projects was to video the effects of the El Nino on the seal nesting season in California. As in Peru, the cold waters become warm, the bloom slows and the fish go away, with less fish the mother seals have no food so, cannot produce milk for their newborns waiting on the beach. As horrible as it sounds, and was to watch in Mike’s film, the mothers eventually abandon the newborns to starve.
The video we showed at Sea Lab followed marine biologists studying corals along the western coast of Central America. Here the waters were warming as well, warmer than normal, and the corals were stressed and dying. With orbiting satellites now in place oceanographers were able to view this event from space and watch the entire thing unfold. These images showed that during a normal year the western Pacific had cold water along California and much of South America. The waters along western Central America were warm. But during an El Nino year, warm water replaced the cold, particularly near Peru. Scientists were able to connect several events to El Nino seasons. Increases in wildfires in the western US, people were viewing the northern lights at lower latitudes, droughts occurred where it was usually wet, floods occurred where it was usually dry, and during one El Nino season the Atlanta Falcons made it to the NFL playoffs. Weird things were happening.
The obvious question for science is what drives these El Nino events?
It is understood that our weather and climate are driven by ocean currents. The “dry air” everyone talks about in the western US is driven by the cold California Current. Likewise, the “humid air” of the southeastern US is driven by the warm Gulf Stream. If you alter these currents, you alter the weather and climate of the region. How do you alter ocean currents?
Warm water in the eastern Pacific indicates an El Nino season.
Graphic: NOAA
In the 1980s, when I was teaching at Dauphin Island Sea Lab, the video suggested a connection to sunspots on the surface of the sun. At the time, they were not sure whether the increased sunspot activity triggered the El Nino, or whether there was something else going on, but there was a correlation between the two.
One explanation comes from a textbook on oceanography I used when I was teaching marine science during the 1990s1. It explains the event as such…
During “normal years” cold water from the Arctic and Antarctic runs along the western coasts of North and South America – both heading towards the equator. Once there, the earth’ rotation moves this water westward towards Australia and Indonesia, warming the water as it goes.
Apparently, the ocean currents cannot transport and disperse these warm waters effectively once they reach the western Pacific. Thus, warm water begins to build there.
This accumulating warm water seems to reverse the trade winds that normally flow from the eastern Pacific to the western along the equator. This wind reversal occurs between November and April. It mentions that in the late 1990s the cause of this wind reversal was not well understood.
This wind reversal is often followed by the development of twin “super typhoons” (very strong typhoons) north and south of the equator.
The extreme warm water in the western Pacific affects the weather in the region and this “heat mass” expands spatially. During this expansion, the high-pressure system that sits over the eastern Pacific, bringing them the dry air we know California for, weakens. At the same time, the normal low-pressure system over the western Pacific weakens and, in a sense, things are flipped. This atmospheric change is called the Southern Oscillation, and the entire event was termed the El Nino Southern Oscillation (ENSO).
The power of the typhoons moves warm water from the western Pacific across the equator to the America’s. The waters there warm and the historic El Nino occurs. This movement takes several months.
The El Nino will persist for one to two years. When the warm water eventually releases its heat, the waters cool, and normal conditions return. Until the next El Nino forms.
In the 1990s they had already noticed an increase in the frequency of El Ninos (based on old fishermen’s logs). They suggest climate change may be driving this.
During El Nino years weather patterns change globally, as mentioned above. This altering of the weather impacts all sorts of biological processes, as mentioned above.
Often, the “return” of colder water along the western Pacific “overshoots” normal temperatures and the ocean becomes colder than normal. This has been termed the La Nina.
I kind of imagine the whole process like a sloshing pool of water flowing towards one end of the pool, bouncing off and sloshing back to the other. But instead of water “sloshing around” it is temperatures.
But this was 1996. Have scientists learned anymore about this event?
Not much has changed in their explanation, other than we are much better at predicting when they will happen and alert the public so that farmers, fishermen, fire fighters, etc. are prepared. They do seem to be increasing in frequency.
For the 2024 El Nino, which NOAA began alerting the public in the summer of 2023, they are predicting it to continue for several seasons2. There is no doubt that this winter is colder than normal. The Florida panhandle also experienced a drought this past fall. But… during most El Nino years, hurricanes are few in the Gulf of Mexico. We will see, and watch, how the rest of the year rolls out.
Reference
1 Gross, M.G., Gross, E. 1996. Oceanography; A View of Earth. 7th edition. Prentice Hall. Upper Saddle River, New Jersey. Pp 472.
2 El Nino / Southern Oscillation (ENSO) Diagnostic Discussion. Jan 11, 2024. National Weather Service Climate Prediction Center. National Oceanic and Atmospheric Association.
