THE SEA OF LIFE
As we celebrate United Nations World Ocean Day on 8 June, our knowledge of the power and fragility of our oceans still has a long way to go.
Ican see the sea!” my brother and I would shout out in unison as we crested the hill at Mariakani, one of the coastal settlements overlooking the port of Mombasa, where the East African coast meets the Indian Ocean. It was that first glimpse of the sea that marked the end of a long journey, and the start of our family holiday.
The journey began in Nairobi, and always before dawn. Our cherry-red Datsun 120Y would be loaded up with bags and sandwiches, headlights on, engine running and my dad, drawing on the first of many cigarettes, would wait impatiently for his bleary-eyed brood to get ready.
This was the early 80s. Kenya, with its post-colonial borders shaping a new national identity, was a young country and we were a young family on a trip to the seaside. The draw was the Indian Ocean. I can still remember how the smell and feel of the air changed as we left the highaltitude city of Nairobi, with its cool, dry atmosphere giving way to the dusty, hot savannah air that, in turn, slowly became warm, humid and salty as we made our gradual descent to the coast.
What I didn’t know then, which I do now, is that on that journey my senses were awakened to an ancient and invisible dance. Powered by the sun, this is a molecular exchange where energy, minerals, nutrients and water are perpetually cycled between the ocean, land, air and all living things. Known respectively as the hydrosphere, geosphere, atmosphere and biosphere, the reality is these realms have no real boundaries and, in the past 30 years or so, scientists studying this ‘dance’ have come to view the Earth as a single system, in which the ocean plays a major part.
Earth is, in fact, an ocean planet. More than two-thirds of its surface is covered by ocean, but it does not dominate by sheer volume alone; the physics, chemistry and biology of the stuff create a superb and intricate system that is dynamic and fluid, yet holds everything in balance to make life on Earth possible.
One of its important functions is to store the heat that arrives from the sun, which is then distributed around the globe. The ocean is also vital for soaking up the carbon dioxide from the atmosphere, absorbing it into the hydrosphere where it is eventually locked away in the geosphere, as it reacts with limestone sediments on the seafloor, as well as becoming incorporated into the biosphere in the bodies of plants and animals.
All this works, among other things, to regulate the temperature of the Earth and, since the start of the Industrial Revolution, the ocean has been a buffer that has slowed down sharp rises in global temperatures. These would otherwise have been felt much sooner with the advent of burning fossil fuels (the first prediction of global warming was made as early as 1843, by the German naturalist Alexander von Humboldt). The higher heat capacity of water, compared to the air, has meant that the ocean has absorbed 93 per cent of human-induced warming so far. On this count alone, I want to drop to my knees in humility, gratitude and reverence to this immense force of nature. Clearly my inner animist is alive and well. Then again, even without this knowledge, I have always felt the pull of the ocean.
As a child, I couldn’t bear having to wait until my folks had unloaded the car and stocked up our holiday rental with food. This was all mindlessly boring business getting in the way of that first plunge into the Indian Ocean. As far as I was concerned, only then had we truly arrived. From that point on, I would spend the whole day in the water, except when I had to eat and wait one excruciatingly long hour for my food ‘to go down’ (cue lots of eye-rolling). But the second I was given the go-ahead, I was back in the water.
I had the most rudimentary of masks but it was a prized possession because this was my ticket to an underwater world of wonder. But, I have to confess, I wasn’t an entirely fearless explorer. I mostly hovered over clear patches of sand, whose only features were rows and rows of wave-sculpted ridges. Oblivious to the ospreys and terns flying overhead, my eyes were trained down below, always on the lookout for chani, the dreaded sea urchin Astropyga radiata. Its reputation for piercing venomous spines and painful wounds gave me every reason to be wary and in awe of the sea all at the same time. Thankfully, the urchins’ inky black spines made them easy to spot against the powderwhite sand, so that is where I would remain, diving again and again, deeper and deeper, holding my breath for longer and longer each time. I loved being underwater and the feeling of weightlessness, but most of all, I just loved the way this world washed out the sound of the one above. I still do.
Over the years, fear has given way to fascination and, whether I’m scuba diving, snorkelling, or simply swimming in the sea, getting into the water always feels like a homecoming to me. For the past 10 years, I have made my home in Cornwall and gone are the days when I would stick to the clear and monotone sandy seabed. With so much to explore, I head straight to the rocky reefs and kelp forests with their colourful wrasse, maybe catching a lucky glimpse of the beautifully camouflaged smallspotted catshark gliding among the gently swaying fronds.
Time spent in the sea reminds me how to stay playful in my adult life. Even though I am far from my childhood home and family, to my mind, the ocean is what connects me to those roots. Astonishingly, this might not be as fanciful as it sounds.
From ecologists to oceanographers, scientists are coming to understand the idea that everything is connected, as it seems that everywhere we look, a world of synergies and partnerships is being revealed. We find them in our bodies, now known to have more bacterial cells than human cells. We find them in forests, where trees share information and resources. And we most certainly find them in our oceans. To try to model the full complexity and interconnectedness of the oceans, researchers have had to join forces to explore the reality that the biology, geology, chemistry and physics of the ocean are all intimately linked. This study of the connectedness of everything has the more pragmatic name of ‘biogeochemistry’. My closet hippy is delighted to learn that this multi-disciplinary approach has enabled huge strides in our understanding of ocean systems and how they are connected.
Perhaps the most important breakthrough has been the discovery of a single, unbroken current that threads its way, like a ribbon of water, connecting all of the world’s oceans. It is a journey that is thought to take 2,000 years to complete, as a stream of dense, cold, saline water flows through the deep ocean. It follows a meandering but distinct path that links the Atlantic, Indian and Pacific Ocean basins, gently stirring and cooling these water bodies as it goes. The cold, saline, deep current is matched with warm surface
“The reality is that the biology, geology, chemistry and physics of the ocean are all intimately linked.”
currents such as the southerly Agulhas Current, which runs the length of Africa’s south-east coast and, of course, the Gulf Stream that famously (and mercifully) keeps Western Europe and the British Isles warmer than their northerly latitudes would have otherwise allowed.
But all that is changing. Climatologists have been keeping a close eye on a region of ocean known as the ‘cold blob’, located in the open waters of the North Atlantic. Roughly in line with the southernmost point of Greenland, this is the region where the cold, deep, saline current begins its bimillennial journey. But as the Greenland ice sheet melt accelerates, fresh water pooling in this region threatens to stall the ocean system of currents. This is thought to be one of a number of global climate tipping points. Another climate prediction appears to be coming true, as data published earlier this year confirms that there has been a consistent and marked slowing of the current known as the Atlantic Meridional Overturning Circulation that drives this part of the ocean current system, which holds the climate in its present configuration.
The first official report about the threat of human-induced climate change was presented to the US government in 1965 (a whole decade before I was born) and it’s taken 50 years of arguing to get to an agreed plan, which we know as the Paris Agreement of 2015. We’re still not even close to being out of the woods. This year’s Earth Day in April did see governments step up their targets and ambitions, but the cold blob is a quiet yet ominous reminder that Earth systems have run out of ‘patience’ and capacity to keep things in balance.
As I look back on my life so far, from those duck-diving days in the Indian Ocean to my life now in Cornwall, I know
I have contributed to the problem. I also know that, like so many of us, I am desperately trying to be part of the solution as well. We can all do our bit but, if we’re going for the biggest gains per unit effort, we need the handful of fossil fuel companies (according to the Climate 100 Index, just three companies emit three times more carbon into the atmosphere each year than all UK households combined) to do their bit.
So, on this month’s World Ocean Day on 8 June, let’s engender a sense of wonder for what we can rightly call our global ocean, but reflect on how to foster a legal and political system that recognises the oneness of the ocean and the Earth as a whole, because we now know that there is scientific merit in allowing ourselves to think this way.