A Life on Our Planet - David Attenborough

Introduction

• Humans are the only ones in earth powerful enough to create worlds— and then destroy them
• Tragedy of our time (brought about by ourselves) = staggering loss of biodiversity

Part 1: My Witness Statement

• Human’s capacity for extensive culture = singular among life
  • Since over 10,000 years ago, humans have not physically evolved much— but our culture has
    • Impetus for this = change to a more stable climate conducive to settling, agriculture
    • Holocene (“our” era) → uniquely stable in Earth’s history; perhaps moderated by biodiversity— carbon captured by phytoplankton, animals keeping grasslands fertile, mangroves → stabilized ocean ecosystems; rainforests doing their thing; reflection from ice sheets at poles
• Serengeti = “endless plains”
  • 1960s → researchers realized that grasses were dependent on grazers as much as the other way around; needed to be periodically cut down
  • Example of intimately interconnected ecosystems— interdependent, but not robust; very susceptible to collapse if one species was disturbed
• 1968: first pictures of Earth from space, Apollo 8
  • Emphasized that nature is finite, that Earth is small and uniquely precious

  There is an edge to our existence.

• 1978: filmed mountain gorillas with Dianne Fossey in Rwanda; meant to talk about the evolutionary significance of the opposable thumb
  • Such a powerful experience to interact with gorillas, bc their senses are so similar to ours— they experience the world much as we do; live in similar social groups
  • We have an obligation to protect them as our cousins; they are not the dangerous and violent beasts as often portrayed, but peaceful and intelligent creatures
• Quest to film world’s biggest animals: whales
  • Critical role of “whale pump” to maintain the fertility of the open ocean, moving nutrients from the depths by feeding, pooping → industrial whaling threatened this whole system
• Rainforests = unique example of 3D habitat on land
  • Stability of climate (no seasons) → sense of timelessness encourages biodiversity, evolutionary innovation and experimentation
  • Extremely interconnected ecosystem, single species pairs dependent on each other
  • Deforestation of such is hard to accept, but just the continuation of what has been done by Europeans, etc.
    • Double incentive to clear forest: timber from the trees, and land to cultivate oil palms
• Oceans → covers 70%+ of surface, but depth → makes up 97% of habitable space on Earth
  • 1997: BBC decided to film The Blue Planet
  • Rapid technological and cultural developments → human skill at fishing grew exponentially, but fish have limited capacity for reproduction
    • By end of 20th c, had removed 90% of fish in coastal waters
    • Tendency to take the biggest fish = especially harmful— bigger fish produce the most eggs; also interfering with food chains much more complex and delicately balanced than many on land
  • Filming began at same time as bleaching of coral reefs was first observed
  • Soon realized effects of global warming were being masked bc oceans absorbing much of heat, so air temps were constant.. wouldn’t last forever
• 2011: filming for Frozen Planet occurred with sea ice very vulnerable
  • Ice supports algae growing on underside, which in turn supports the polar marine ecosystems— up to whales, fish that we catch → as winters shorten, ice around for less time, less algae which destabilized the whole system
  • Seen in signs like diminishing size of polar bear cubs, crowding of walruses on beaches (leading some to cliff edges, which they cannot see well, and thus tumble off to their deaths)
• In summary, human impact on the planet is staggering
  • Top drivers of deforestation, land use = cattle pasture, soy farmland (much used to feed cattle and livestock), oil palms
  • Very little deep forest left
  • Humans & domesticated animals make up 96% mass of vertebrates on Earth
  • We don’t notice just how much life has been lost bc shifting baseline effect

Part 2: What Lies Ahead

• The Great Acceleration: pattern of virtually every trend since mid-century
  • Human production/activity (GDP), emissions, population, and all the environmental metrics: deforestation, carbon in the atmosphere, etc.
  • Curve is like population growth— currently in log phase, but will eventually plateau, and then, in a finite system, will decline
• Models of ecosystem resilience → 9 planetary boundaries, any of which, if breached, will lead to destabilization of the global system
  • Have already pushed through 4 of them: nitrogen levels (by fertilizer use), deforestation/loss of wetlands, temperature, biodiversity loss
  • Catastrophic decline, an equal and opposite reaction from nature, will follow
• By 2030s…
  • Amazon reduced to 75% original size, which may trigger collapse of entire forest through forest dieback— trees no longer producing enough moisture to form clouds and get enough precipitation → would turn into dry forest and ultimately a savanna; affect climate across SA (droughts); huge loss of biodiversity; huge release of carbon sequestered in the biomass through wildfires
  • Arctic Ocean expected to have first ice free summer → algae on underside of ice sheets will be dispelled, destabilizing marine ecosystem
• In the 2040s: Thawing of permafrost: currently, northern soils = 80% water; melting → massive flooding, landslides, huge shifts in rivers and lakes, release of massive carbon stores (4x as much as humans have emitted, 2x as much as currently in atmosphere)
• 2050s: Acidification of entire oceans → even more destruction and vulnerability of reefs (90%+), inhibition of shellfish and creatures at bottom of marine food chains; eventual collapse of ocean ecosystems
• 2080s: Crises of food production on land— depleted soils, more extreme weather, loss of insects
• 2100s: Forced migration of people from sea level rise, extreme temperatures causing failures of agriculture
• How to restore stability? Must restore biodiversity

Part 3: A Vision for the Future— How to Rewild the World

• Use planetary boundaries as guide
• Account for inequality of impact: 50% of emissions from top 16% most wealthy → must change unsustainable lifestyles
  • Can add a parallel set of minimum boundaries to the planetary boundaries model → social goals (clean water, education, no hunger, etc.)
• Lessons from nature on how to solve this
  • Moving beyond growth: with finite resources, cannot have infinite growth, but this doesn’t mean no change
    • Ex. forests can continually thrive without demanding more and more resources
    • Initial steps = sustainable/green growth (circular economy, expanding in low impact ways, renewables), but ultimately growth is still growth
    • New Zealand = example of this: dropped GDP as measure of progress, instead using metric combining people/planet/profit
  • Switching to clean energy
    • Ex. Morocco has little fossil fuel resources, but now powered almost all by its own solar power, storage with molten salt tech
  • Rewilding the seas
    • Studies show that more biodiverse ecosystems → more carbon capture, more fish produced
    • Restoring marine ecosystems → capture carbon, raise biodiversity, increase food supply
    • Establish no-fish zones → allow some fish to grow older, spillover effect into surrounding regions will occur after several year delay; ideal fish nurseries like mangrove forests, salt marshes also have most capacity for carbon capture; could establish all international waters as MPAs → seed coastal waters with fish
    • Move to more sustainable, selective fishing practices: more transparency in supply chain, monitoring of yield and populations (Palau = good example)
    • Reached “peak fish” capture in 1990s, but demand has continued to grow, met by farmed fish— which, when some sustainably, can be a great option
    • Supporting growth of kelp forests → food for people/livestock, biofuels, source of other biomolecules
  • Taking up less space: land use for agriculture currently takes up over 50% available land → primary driver of biodiversity and carbon emissions
    • How to get more food from less land? Can learn from some examples in the Netherlands, which is very densely populated
    • Regenerative agriculture: reduce fertilizer and increase yield by rotating crops, inter-cropping, cover crops, etc.
    • Shifting to more plant-based diets: beef production takes up extreme amount of land for small amount of calories (grazing land, agricultural land to grow feed)
  • Rewilding the land
    • Focus on stopping deforestation, especially of rainforests; current attempts by REDD+ to put a value on wild land for carbon capture services (a good start, but also need to account for value of biodiversity!)
    • Ways to benefit from and preserving value of biodiversity (necessary to have engagement of local/indigenous people) = searching for functional organic compounds, sustainable logging, eco-tourism (ex. Masai in the Serengeti)
    • Practices like silvopasture, agroforestry can boost biodiversity of already-cleared lands/farms (Neb? farm in Britain)
    • If big enough regions of land united, introduction of top predators helps foster biodiversity through trophic cascade (ex. wolves in Yellowstone)
• Planning for peak human: currently operating far above Earth’s capacity; to sustainably live within these bounds, population growth must stop
  • At national level, countries follow four-stage demographic transition with economic development that ultimately stabilizes with low birth and death rates, stable population
  • Similar trend at global level; but will be a long time until we reach “peak human” due to “fill-in effect,” rising life expectancy
  • How to reach peak human at lower level, faster? Most effective way = helping developing countries through demographic transition— basically, improving the lives of citizens in any way
    • Especially empowerment of women, more widespread & better education (all things we should be doing anyway)
  • Potential fifth stage of demographic transition → population decline (Japan); word population could ultimately stabilize at current levels by end of century
• Achieving more balanced lives:
  • Circular economy → would comprise two cycles, a biological one (organic materials, that can all be utilized for energy, capture all carbon), and technical (plastics, metals, etc. that have to be reused/recycled); materials that don’t fit into either (CFCs, etc.) would not be used → ultimately no pollution
  • Harness efficiencies of dense urban living; integrate as much green space as possible (Singapore).. most sustainable buildings today net producers of renewables, can filter own water, etc.