A perspective on DANA, Valencia

After three years in which the planet's climate has experienced a phenomenon known as La Niña, in 2023 it gives way to its opposite, El Niño. This has led the World Meteorological Organization to warn that this event, added to climate change, could cause the 1.5 °C limit to be exceeded in the next five years. But what are these "children", how do they affect Spain, how long will they last?” are the questions asked by Science Media Centre (SMC) Spain in May of 2023 [1]. The 1.5 °C ceiling referred to here, is the limit set by The Paris Agreement for long-term global average temperature.

But first, what are El Niño and La Niña? Spanish for “little boy” and “little girl”, El Niño and La Niña are opposing phases of the El Niño-Southern Oscillation (ENSO) cycle [5]. The ENSO cycle is a self-explanatory alternation of these effects that impact sea-surface temperatures [2]. These two climate patterns are triggered by human-induced climate change and break normal conditions in the Pacific Ocean, a prominent example being up- and downwelling [2,5].

Upwelling and downwelling are processes caused by winds that affect ocean ecosystems and nutrient distribution. Upwelling occurs when winds push surface water away from an area, causing colder, nutrient-rich water to rise from depth (“well-up” from below) and replace it.

The reverse of this is downwelling, when winds cause surface water to accumulate along a coast and force the water to sink. Downwelling helps to distribute oxygen and heat deeper in the ocean (a boost to biological productivity), but generally reduces the availability of nutrients near the surface, which can reduce biological productivity. Both processes play a crucial role in the health of the oceans and the global climate system [6].

El Niño is characterised by warmer-than-average sea surface temperatures in the central and eastern Pacific, while La Niña is characterised by cooler-than-average sea surface temperatures in the same region [2]. The key is "above average". The interplay between these phenomena and climate change, which is intensifying not only across the Pacific but also globally, is posing significant threats to the planet.

El Niño and its effects on the world currently

There are countless stories that emulate, almost perfectly, the tragedy of Nauru. However, it is important to acknowledge the potential of globalism in wealth creation, without all of the consequences. A contrasting example of the approach to Globalism most nations take is Bhutan. The country’s government, most famous for its adoption of the gross national happiness index, is dedicated to the preservation of Bhutan’s culture and environmental heritage. In fact, in the constitution of the country, Bhutan is obliged to maintain 60% of its land area to forest [8]. This extreme protectionism expands to tourism, mining, energy production, foreign direct investment and any other economic activity that can disturb the government’s mission of preservation. As researcher Reinfeld discusses [9], the government’s philosophy is to invite the global world only to the extent that it does not homogenize the country’s culture or disturb its environment. The largest source of revenue for the country: carbon credit trading and renewable energy. Bhutan’s hydroelectric plant provides 50 million USD in carbon offsetting credits[11] , overall the total of energy and carbon offsetting results in 80% of the government’s annual revenue. These revenues over the past decade have allowed investments into education and healthcare in order for the population to enjoy a steady increase of HDI from 0.54 in 2014 to 0.666 in 2021. [10]

In a demonstration of ‘ladies first’, from 2020 to 2023, La Niña dominated the Pacific, leading to cooler ocean temperatures and influencing global climate patterns, before El Niño returned in 2023, bringing with it the heatwave in the summer of 2023 [2]. Generally, El Niño and La Niña episodes last between nine and twelve months, although in some cases they can extend over several years. This cycle takes place on average every two to seven years, but does not follow a consistent pattern or schedule, although historically El Niño events tend to occur more frequently than La Niña episodes [5].

As mentioned before, El Niño and La Niña interfere with the natural pattern of up- and downwelling of oceans, their cyclical changes having a direct effect on the strength and distribution of upwelling and downwelling [2]. At the time of the El Niño phenomenon, warmer sea surface temperatures in the central and eastern Pacific reduce the intensity of upwelling on the west coast of the Americas. It causes the usual nutrient-rich water that rises to the surface to be suppressed and increases the effect of downwelling. La Niña in turn strengthens the upwelling in these regions, as by cooling sea surface temperatures below the average and with increased trade winds, the upwelling of nutrient-rich deep water increases [2,7]. Nevertheless, it is important to note that El Niño, however much it influences our climate, is one of several factors that affect global and regional climate. The magnitude of its indicators does not directly determine its impact, as El Niño events are unique in their distribution and intensity of impact.

El Niño's impact on global temperatures is typically observed in the year following its formation [2]. In this context, let us take a look at the data from last year.

After a strong onset of El Niño in July to August 2023 followed by a slight moderation in September, the World Meteorological Organization (WMO) forecasted (in November of 2023) that El Niño would last at least until spring of 2024 and increase temperatures on land and sea [2]. The temperatures of 2023 have hit a new record, making it the warmest year since 2016, in fact the past decade (2015-2024) was confirmed as the warmest since records began, with ocean warming accelerating and ice loss increasing [4]; an increase from 0.5°C above average in May to about 1.5°C above average in September 2023 was recorded. This is not only caused by the El Niño effect, but "[...] [t]his is clearly and unequivocally due to the contribution of the increasing concentrations of heat-trapping greenhouse gases from human activities,” states WMO Secretary-General Prof. Petteri Taalas [2].

The previously mentioned 1.5°C above average temperature measure in 2023, increased to a global average temperature of 1.54°C in 2024, while The Paris Agreement aims to limit the long-term global average temperature increase to well below 2°C and to pursue efforts to keep it under 1.5°C [4]. WMO Secretary-General Celeste Saulo, however, clarified that temporary temperature spikes above 1.5°C should not be confused with a permanent exceedance. That is, because short-term fluctuations caused by natural phenomena such as El Niño can cause annual or monthly anomalies, but are different from the sustained average increase over decades. Nonetheless, Saulo emphasised that every fraction of a degree matters and increases the likelihood of severe climate extremes and impacts [4].

In regards to to greenhouse gas emissions, Saulo brings added emphasis on the statement made by WMO in the previous year: “Every month since June 2023 has set a new monthly temperature record – and 2023 was by far the warmest year on record. El Niño has contributed to these record temperatures, but heat-trapping greenhouse gases are unequivocally the main culprit,” [3]. This highlights the concern that El Niño alone cannot explain these irregularities.

The correlation of El Niño and a changing climate is thus pivotal. Warming oceans lead to rising sea levels, leading to an increased risk of coastal flooding and other disasters. This is due in large part to the contribution of El Niño, where excess rain falls back into the oceans, whereas in La Niña years it tends to fall on land. Current monitoring by NASA shows that these sea level impacts are part of a broader human-induced sea level rise trend that poses major challenges to coastal communities worldwide [7].

Spain/Valencia

One example of a "coastal community" that was recently hit by flooding is Valencia. It experienced a year's worth of rain in just 8 hours, caused by a weather phenomenon known as Depresión Aislada en Niveles Altos (DANA). In English, it refers to the meteorological term "cold drop", an event in the western Mediterranean that leads to heavy rainfall and flooding. The term "DANA" is used by Spanish meteorologists to describe this weather phenomenon. It occurs when cold polar air drops over the warmer Mediterranean region, creating instability that triggers severe storms.

Killing more than 200 people and causing massive damage to infrastructure, the DANA forced school closures with a red alert in several provinces and the search for missing persons remains ongoing [9].

Unfortunately, the devastation and high death toll have given rise to misinformation and conspiracy theories linking DANA to climate change conspiracies, although “[d]espite having historical records, [...] data’s statistical length is insufficient to definitively attribute this DANA to climate change,” Juan Ballesteros, CSIC (The Spanish National Research Council) researcher at the National Museum of Natural Sciences (MNCN) [9].

Emilio Santiago, a senior CSIC scientist and expert in climate anthropology, spoke about ‘a growing trend’ - an emerging wave of climate change denialism. Santiago explained that instead of an increased raise of awareness about climate change, conspiracy theories are on the rise. "We are witnessing the birth of conspiracy denialism in Spain, which was a fairly residual phenomenon in our country," he noted [see 9]. He linked this to a general crisis of confidence in democratic institutions due to the economic crisis of 2008, which is undermining trust in science, journalism and politics.

As a consequence of this mistrust, political actors that reinforce mistrust, climate-related false reports seem even more credible. “It is important to start talking about climate change as a national security problem,’ argued Santiago [see 9].

A Call for Action

In response to DANA, Ballesteros spoke in favour of adapting infrastructure and urban planning. He advocated measures such as improving the connection of rivers to floodplains, the creation of flood-proof zones and the use of vegetation to mitigate the consequences of flooding. At the same time, he recognised that there is no "zero-risk" scenario. Santiago stressed that it was not practical to relocate entire populations from flood-prone areas and that management of the population in flood zones was needed for a more successful plan. “There is no society that can administratively, politically and economically manage to move that volume of population. That is not realistic,” he emphasised, pointing to the need for a stronger emergency response system. Improved early warning systems were also suggested. Ballesteros focussed on the importance of timely warnings in torrential water catchment areas, where response time can be only a few minutes [9]. This goes hand in hand with the concept of WMO’s "Early Warnings For All" campaign, the global initiative that amidst ongoing climate change and climate change denialism, emphasises the urgency of proactive measures to minimise economic and life loss by giving regular updates on weather extremes linked to phenomena like El Niño, greenhouse gases and other factors [3,8].

Pressing the need for climate action, The WMO State of the Climate 2024 report issues a "Red Alert" about the rapid pace of climate change driven by escalating greenhouse gas emissions. 'The warmest decade' has experienced unprecedented warming, ice loss, sea level rise and severe weather disruption. "El Niño events have a significant social and economic impact," according to WMO Secretary-General Celeste Saulo, her term for the visible effects of current climate change being a “[...] foretaste of our future” [see 4]. Accurate seasonal forecasts are therefore crucial in helping countries prepare and limit damage to climate-sensitive sectors such as agriculture, water resources and health, and early warnings of extreme weather for saving countless lives [4] and yet only half of global countries consider themselves to have adequate early warning systems for multiple hazards [8].

Final Remarks

Not to say we are the sole perpetrators of existing climate change and greenhouse gas emissions; rather, we can feel and see the impacts of it and that should feel like a call for action. UN Secretary-General António Guterres emphasised that "climate catastrophe is hammering health, widening inequalities, harming sustainable development, and rocking the foundations of peace." [see 4] “Every fraction of a degree of warming matters to our planet, to our lives, to future generations” (see [4]), so we need to make the right decisions to minimise and delay the changes that are already rapidly in progress.