Even if we manage to survive the mid-century environmental apocalypse predicted by UN-certified scientists, the fin de siècle holds some bleak news for the blue planet.
A recent study by the Massachusetts Institute of Technology (MIT) predicts that Earth may lose its distinct blue hue due to climate change and global warming by the end of the 21st century.
Much of the planet’s ocean surface will change in within 80 years, leaving it visibly altered, the study says, until it no longer resembles the “pale blue dot” from outer space.
The study, published in the scientific journal Nature Communications, attributes this to the rapidly changing composition and of phytoplankton (or algae), in a way akin to large-scale bleaching of oceanic coral reefs due to increased temperatures.
In other words, oceanic ecology is on track to bite the dust by 2100.
What does the study say?
Significant changes to phytoplankton will likely cause a noticeable difference in the of 50% of its oceans, intensifying its blue subtropical and green polar regions in particular, according to author of the study and principal research scientist at MIT, Stephanie Dutkiewicz.
“It could be potentially quite serious. Different types of phytoplankton absorb light differently, and if climate change shifts one community of phytoplankton to another, that will also change the types of food webs they can support,” Dutkiewicz added, implying this will have ramifications beyond a shift in the planet’s .
How are algae linked to navy blue anyway?
The ocean’s colour depends on how sunlight interacts with the type and amount of oceanic life in a particular region. While water molecules absorb almost all sunlight except for the blue part of the spectrum, which it reflects back, the presence of organisms in the ocean changes that. This is why relatively barren open-ocean regions appear deep blue from space, but vegetated portions absorb and reflect different wavelengths of light.
Phytoplankton, which absorb blue portions of sunlight to produce carbon for photosynthesis, and less of the green from the spectrum. As a result, more green light is reflected back out of the ocean, giving algae-rich regions a greenish hue.
So, what’s happened to the now?
The scientists conclude that a concoction of global warming and natural weather-related phenomena has, over time, resulted in periodic changes in the aquatic chlorophyll. They also suspect that significant climate-driven change in chlorophyll could occur by 2055, earlier than previously thought.
As a result, regions with typically greener waters, such as near the poles, may turn a deeper hue, as warmer temperatures creating larger blooms of more diverse phytoplankton. The same will happen to blue subtropical waters, which will possibly turn bluer, reflecting even less phytoplankton and life than they do today.
How did the study arrive at this conclusion?
For the study, the researchers developed a global model that simulated the growth and interaction of different species of phytoplankton, previously used to predict phytoplankton changes with rising temperatures and ocean acidification. It analysed information about phytoplankton, including what they eat and how they grow, incorporating the data with factors like ocean currents.
When they increased the global temperatures up to three degrees Celsius by 2100, they found wavelengths of light in the blue or green wave band responded the fastest.
The extent of in global temperatures predicted in the study tallies with that in IPCC’s landmark report last year, and will likely occur in a scenario with little to no political action taken to combat climate change by reducing greenhouse gases.
How does this affect you?
The change is only a symptom of a larger problem and may even be invisible to the naked eye, Dutkiewicz notes. But the peer-reviewed paper does sound an early warning of wide-scale changes to marine ecosystems.
Climate change and global have already caused irreversible damage to reams of coral colonies. But this is the first time a study has been conducted to reflect how it is changing the make-up of phytoplankton, the very basis of aquatic life, and by extension, the of the oceans.
“If climate change shifts one community of phytoplankton to another, that will also change the types of food webs they can support,” the study notes in what is perhaps most dire warning. Aquatic life feeds on plankton; any change in the food chain will reflect on their populations, perhaps even alter their composition. For countries with a significantly long and enriched continental shelf and populated coastline, like India, this poses a huge threat to coastal settlements that depend on fishing for nutrition and economy.
Prarthana Mitra is a staff writer at Qrius