“Came the Spring with all its splendour,Henry Wadsworth Longfellow, The Song of Hiawatha (1855)
All its birds and all its blossoms,
All its flowers, and leaves, and grasses.”
Spring. Or, more appositely, Spring! Rebirth, rejuvenation, renewal, resurrection and regrowth. That time of year when new life courses through the earth and into the flowering plants and trees, the sun arrives earlier each day and departs later (and appears warmer), the beaches are more appealing and life generally has a spring in its step. Here in the southern hemisphere Spring conventionally runs from the 1st September until the 30th November, but Mother Nature doesn’t necessarily work off the same calendar as us humans. To be a little more scientific, spring’s arrival on any given year is based on biological indicators and is known as phenology. (Not to be confused with phrenology, which is a pseudoscience that believes that mental traits can be assessed based on the shape of bumps on an individual’s head. Not recommended as a replacement for neuropsychology.)
Phenology is a somewhat more scientifically precise science (certainly than phrenology) in that it is a study of periodic plant and animal life cycle events and how these are influenced by seasonal and interannual variations in climate. The word itself has a beautiful root; coined by Belgian botanist Charles Morren in 1849, it is based on the Greek root phainō, meaning ‘to show, to bring to light, to make appear.’ Which is the essence of spring, after all. Phenologists ignore the calendar: they look to nature in its various forms to watch the seasonal changes. The flights of birds, the arrival of butterflies, the emergence of leaves and flowers, the timing of the developmental cycles of temperate-zone honey bee colonies; the egg-laying cycles of amphibia and, here in the Western Cape, the behaviour of migratory whales. In this day and age of potential global warming, phenology serves another great function: because the various measuring criteria are so sensitive to small variations in climate – especially to temperature – phenological records can be a useful proxy for temperature in historical climatology. Proxy in this sense means climate proxy: preserved physical characteristics of the past that substitute for actual measurements. Examples are ice-cores, tree rings (or dendrochronology) and lake and ocean sediments. (Isn’t it absolutely incredible that bubbles trapped in ancient ice hold air dating back millions of years?) Combine all these sciences and a very accurate graph can be drawn of temperature reconstruction, and the signs are all unfortunately pointing in the wrong direction.
‘Season creep’ is another somewhat less than romantic term that has come into prominence of late, and it too can be associated with global warming, or at the very least, alterations in the basic season cycles. Season creep, as can be deduced from the term, is the tendency for seasons to arrive earlier (or later) than predicted. Since scientists have been taking note, there has been significant season creep measured by plant phenology: in the range of 2–3 days per decade advancement in spring, and 0.3–1.6 days per decade delay in autumn over the past 30–80 years. Given that a year is only 365 days long (although they feel much shorter), this is a serious warning sign and phenologists are adding their not insignificant voices to the global warming debate. Want more proof? A study from 1978 to 2001 showed that 78% of all leafing, flowering, and fruiting plants advanced their cycles. Nature doesn’t lie. As the American organisation ‘Clear the Air’ puts it: “…natural processes like flowers blooming, birds nesting, insects emerging, and ice melting are triggered in large part by temperature. The delicately balanced system begins to fall into ecological disarray.’ Only humans can fix this; it is certainly time that we started looking at our seasons with more critical eyes, start ignoring profit and politics, and make the necessary changes.
But having said all that, let us enjoy this 2019 spring, whenever it turns up. By celebrating the incredible natural events that occur each year, we can reinforce our desire to work for constructive climate change. Join us for a cruise this spring: pick a day and make an event of the occasion. From the moment you step aboard one of our boats, you will know that spring is here: the tang of the air, the warmth of the sun, the seagulls calling, the clarity of the incredible views. In Table Bay you’ll be surrounded by life; some visible, some, beneath the keel, hidden but very present. With the mountains greened through winter rain and the Atlantic sparkling as the swells roll past, you’ll feel very, very alive. And you’ll know just why spring is such an important time in the lives of every living creature on this planet.