In his book Otherlands, palaeobiologist Thomas Halliday paints a vivid picture of London’s landscape 50 million years ago – a landscape filled with swampy forests, tropical waters, and various prehistoric creatures. The book explores these vanished ecosystems and how they can serve as a basis for predicting the future of our changing climate. I have the opportunity to meet the author for a walk along the riverside, where we will examine modern London and its remnants of past landscapes, while contemplating what the future may hold.
To begin my temporal adventure, I visit Lesnes Abbey Woods, conveniently accessible via the new Elizabeth Line. With its 12th-century abbey ruins, ancient forests, and bronze age tumulus, this area has always felt like a journey through time. As I follow the signs to a fossil bed, I am surrounded by squirrels and squawking green parakeets. At the fossil bed, both young children and older kids are engaged in the exciting task of searching for 50-million-year-old shells and sharks’ teeth. It is here that I encounter a wooden coryphodon, an extinct semi-aquatic mammal that once roamed this area.
Continuing my journey, I follow the Green Chain walk towards the river, where it merges with the Thames Path. In a hurry to reach our meeting point before low tide, I pass by remnants of the river’s history, including piers, jetties, and concrete pillboxes from World War II. Finally, at Tripcock Ness, near the iron Edwardian lighthouse, I find Thomas. Together, we explore Gallions Reach, a stretch of the river in search of clues to its ancient topography. Here, we discover the remnants of a 5,000-year-old drowned forest, exposed during low tide. These trees, as old as Stonehenge, provide a glimpse into a time when mammoths still roamed the Earth.
Continuing west along the Thames Path, I notice the new signs of the King Charles III England Coast Path, a part of the ongoing project to create a 2,700-mile path around the English coast by the end of 2024. Along the path, I encounter various bird species, including bar-tailed godwits, shelducks, and black-headed gulls. Thomas informs me that all birds are descendants of dinosaurs and explains the evolutionary connection between the two.
As the rain begins to fall, we make a detour through Maryon Park to visit Gilbert’s Pit, an old quarry that offers a unique view of London’s bedrock. The layers of different colors represent lost worlds of mangrove swamps and prehistoric landscapes. Moving forward, we pass by the Thames Barrier, a structure that has protected London from flooding on numerous occasions. An explanatory panel informs us about the Thames Estuary 2100 plan, which addresses the potential impact of climate change and rising sea levels.
Heading towards Greenwich, we reach the cable car at the North Greenwich Peninsula. From the cable car, we observe the Lea, a relatively young river that formed only half a million years ago when the Thames was redirected due to an ice formation. We also catch a glimpse of the hills of Greenwich Park, which were created millions of years ago during the collision of Africa and Europe.
With thoughts of the Earth’s ancient past and the potential consequences of climate change, we end our journey at Royal Victoria station. Our walk has provided us with both a sense of awe and a realization of the fragility of ecosystems, reminding us of our place in the natural world.