Chapter 3: The Mare Nostrum Thermometer

The gentle rocking of the waves cradles the boat, but Josep Pascual remains unfazed. Standing at the stern, his white hair tousled by the breeze, he holds a set of papers attached to a wooden board with clips and makes continuous notes. In the background, a white cloud rises imperial and fluffy over the Medes Islands, off the coast of l'Estartit in northern Catalonia. When he finishes writing, Pascual sighs happily. "What a cloud! It's beautiful, isn't it?" he says. That same transparent enthusiasm, coupled with unwavering perseverance, has turned him into a legend in the world of meteorology at the age of 73.

For half a century, Pascual has been setting sail without interruption every week in a small fiberglass boat to collect water temperature data four kilometers from the harbor, in front of the Medes Islands, where the sea reaches depths of 90 meters. His manually recorded measurements are the longest-running uninterrupted ones in the Mediterranean and hold significant scientific value regarding the impact of the climate crisis on the Mediterranean Sea. "At first, back in those days, we didn't talk about climate change; I measured all these things out of passion. I never thought what I was doing would have value." But it does. His maritime data has been used in several scientific studies, including one by NASA's Jet Propulsion Laboratory.

His passion began with a boat and two jars. When he was 4 years old, Pascual often went to sea with Els Felets, his father, and his grandfather, both fishermen named Rafael. He listened as they scrutinized the clouds and the wind to predict the weather or currents. It seemed like magic to him. At the age of 13, he wanted to forecast the weather himself, so he used two jars and an aspirin bottle to calculate the amount of rain and its evaporation.

Although he initially took temperature data with simple thermometers and barometers, his hobby took a turn when he later studied agricultural engineering in Barcelona and visited the headquarters of the meteorological service. They were surprised by the determination of that young man, so they gave him a precision thermometer and a Nansen bottle. From that moment, in September 1973, Pascual's serious measurements began aboard his family's boat, La fera del mar, and for the past few years, on La pubilla, a five-meter-long vessel given to him by a retired friend.

It's impossible for Pascual to retire from the sea. Single and childless, his day begins and ends in the Mediterranean. With the sound of the waves and the seagulls' cries in the background, Pascual talks as he checks the different instruments he submerges in the water. "This helps me live! If I went a month without going out to measure the water temperature, I'd die of sorrow; it's addictive. Sometimes I've gone out in conditions that weren't reasonable, with two-meter waves... but I feel it was worth it."

After a lifetime of recording maritime data, Pascual is clear about the health of the Mare Nostrum (Mediterranean Sea), and it's not good.

"Climate change? Yes, we should be concerned. The Mediterranean is undergoing tropicalization. The sea is warming. The bad part is that even if we stop accelerating, we're already going at a deadly speed. Future generations will suffer the consequences," he said.

According to his calculations, in the last half-century, the surface and deepwater temperatures have increased by 0.03°C and 0.02°C annually, respectively. "The sea stores heat," he says.

In the Mediterranean, which warms up to five times faster than other seas and oceans due to its closed nature, rising sea temperatures and increasingly frequent heatwaves affect the amount of precipitation on land.

The result will be hunger. The latest report from the United Nations Intergovernmental Panel on Climate Change (IPCC) warns that at the current rate of CO₂ emissions, agricultural productivity in the Mediterranean region will fall by 17% by 2050. Beneath the sea, rising temperatures point to a threat to diversity: Mediterranean plants and animals are highly susceptible to marine heatwaves, as they cannot migrate northward to find cooler waters.

For Pascual, it's important to sound the alarm with reliable data, and his data, scientifically recognized by NASA, is just that. "When the American agency," he proudly explains, "compared my data with theirs from their satellite and saw that they were similar, it made me proud... But the truth is, I thought, 'That means NASA's instruments are working well. I've been coming here every week for 50 years; I know the sea well!'"

According to Joaquín Tintoré, director of SOCIB, the Coastal Ocean Observation and Prediction System of the Balearic Islands, Pascual's work is priceless because, to combat the climate crisis, it's essential to look at the sea. "Climate change is an oceanic problem," he asserts.

An international study involving the Spanish National Research Council (CSIC) supports Tintoré's words with figures: the oceans and seas capture 31% of the CO₂ generated by humans and regulate the Earth's climate.

Tintoré speaks with respect and affection for Pascual's silent but valuable work and admires his endearing determination. "I take my hat off to him. With limited resources, he has demonstrated great perseverance. For those of us who study the oceans, his work is gold."

The recognition from the scientific community is gratifying for Pascual, but as he returns to l'Estartit, his smile fades when talking about the future. "I'm already old, and when I run out of strength, my series of measurements will stop. I don't have children, and there's no one to take over." Despite this, he doesn't give up. Perhaps, he says, he'll have time to convince a student with a similar enthusiasm to continue when he's no longer around. For Pascual, nothing is impossible; it's just a matter of patience, tenacity, and unconditional love for the sea.

This article was produced with support from Internews' Earth Journalism Network. It was first published in La Vanguardia on 02 September 2023 in Spanish. It has been translated to English and lightly edited for length and clarity.

Banner image: Josep Pascual on board "La pubilla" during one of its weekly trips last June, Spain, June 2023 / Credit: Xavier Aldekoa.