Thursday, October 7, 2021

In a 4°C World, the Inexorable Climate Change-Biodiversity Nexus

A 4°C world will reshape the human and nonhuman landscapes of the planet.  That’s axiomatic.  This reshaping, which we could have avoided, will now unfurl beyond our control: Seas will inundate, storms will destroy, drought will parch.  But within our control is how we reshape the landscape in response as we abandon, tear down, migrate, resettle, rebuild, mitigate, adapt.

The latest IPCC report, other blog posts in this series, and Robin Craig’s and J.B. Ruhl’s prescient, unhappiness-inducing article, 4 Celsius, lay out the consequences of a 4°C rise.  The latest report by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) (the IPCC’s more obscure cousin) predicts that more than one million species are imminently threatened with extinction. Those in the know increasingly warn that climate change exacerbates already dire human threats to biodiversity, rendering protected biodiversity redoubts no longer habitable but leaving no places to which to migrate.

As we needlessly hurl ourselves into the 4°C future and as we gobble ever more of Earth’s resources, climate change and biodiversity portend intertwined, grave threats.  Nonetheless, we think of these crises (when we think of them at all) in separate buckets: You over there, think about and tackle GHG buildup and responses; and over here, we’ll think about biodiversity loss. 

It’s time to multitask, to simultaneously envision how conserving biodiversity helps us mitigate and adapt to GHG buildup, and how mitigating and adapting to climate change can and must promote biodiversity. Both because these grave threats are braided and can and should be addressed symbiotically, and for practical reasons -- we only have so much time and money to invest to arrest these cataclysms and sustain a livable planet  we should therefore be merging our approaches to climate change mitigation and adaptation and biodiversity depletion. Think of it as biodiversity mitadaptation.  Biodiversity helps us mitigate GHG buildup; biodiversity helps us adapt to changing ecological regimes; efforts to mitigate GHG accumulation can help or harm biodiversity; and efforts to adapt to climate change can help or harm biodiversity.  In a 4°C future, we must pay a lot more attention to the inexorably linked climate-biodiversity mitadaptation nexus.

Jurisdictions’ pledges to achieve the Convention on Biological Diversity’s ambitious goal of 30% of land protected by 2030 could be synergistic if planners thought: How do our plans to reach 30x30 produce co-benefits if we think of biodiversity as mitadaptation?  How could our nascent plans for nature-based solutions to mitadaptation improve outcomes for biodiversity by specifically incorporating and putting biodiversity’s needs at the center? Because many biodiversity mitadaptation decisions are project based, we need not wait for international or national agreements to think holistically and synergistically.  Consider the following suggestions.

Hernandez et al. describe “techno-ecological synergies” when devising solar energy systems.  In response to mandates to reduce GHGs, large scale solar energy developers produce unintended consequences by scarfing down water and destroying biodiversity. By carefully planning where and how to develop solar and by mitigating the ecological degradation that solar development (currently pegged at nearly half the U.S. energy supply by 2050) causes, developers may minimize damage to biodiversity. For example, to account for demand for ecosystem services to support its solar energy development, the  community-owned Westmill Solar Park in the UK managed and achieved biodiversity benefits by planting native grasses to create pollinator habitat,which simultaneously increases transpiration under the panels, thus cooling them and generating energy more efficiently.

Building artificial, biodiversity-enhancing coral reefs may protect low lying coastal areas from storms and flooding.  In cooler climes, the Netherlands has long battled threatening seas and is now leading the world in learning to live with rising seas by using a “build with nature” philosophy.  The “sand motor” off the coast of the Netherlands provides a model of techno-ecological adaptation to climate change that explicitly attends to biodiversity.  In this pilot project, the Dutch harvested sand offshore (perhaps itself not a sustainable model) to build its buffer island.  The goals of the project explicitly include creation of new habitat for flora and fauna, and at its ten year anniversary, researchers found a rich diversity of shellfish and snails providing food for shorebirds.

Forests are the savior of GHG reduction goals; with net zero or carbon neutral targets depending on “offsetting” the carbon externalities of development, trees are repurposed as carbon sequestration devices.  But win-win-win programs under the aegis of REDD+ usually do not pay sufficient or any attention to biodiversity co-benefits. Ninety-two percent of tree plantation expansion in the tropics between 2000-2012 occurred in biodiversity hotspots, sometimes fueled by carbon offset funds, but seldom with biodiversity/climate change mitadaptation in mind.

When foresters restore land degraded by industrial logging or destroyed by fires, they usually emphasize rapidly growing monocultures and employ biocides to battle “weeds.”  That is, they prioritize short-term economic rather than ecological value. To quote one article, foresters can’t see the forest for the plantations.  The USDA considers it progressive evolution to plant trees uphill 500 feet from where a species has traditionally grown – a few steps uphill in the right direction, but not one that creatively imagines what a biodiversity rich forest will comprise in a 4°C world.  One British Columbia reforesting project, Seed the North, is “Fighting Climate Change, One Sprout At A Time.” They harvest seeds from land neighboring disturbed areas and employ indigenous people (and not just their knowledge) to harvest and cultivate the seeds.  They then use drones to drop diverse, biochar-encased seeds of native species over remote areas.  They aim to create vast carbon sinks composed of native species that sustain greater biodiversity and are better able to adapt to changing climate conditions.

Biodiversity itself may mitigate GHG accumulation.  Schmitz et al. show that animals regulate carbon exchange between the atmosphere and ecosystems in major, not always well understood ways. Predator/herbivore-prey/carbon relationships are complicated. For example, wolves in boreal ecosystems control moose populations, which through altered grazing intensity increase carbon retention in plants.  On the other hand, wolves that prey on elk in prairie ecosystems end up releasing more carbon to the atmosphere.  Living whales store tons of carbon, and their excrement nourishes carbon-sucking phytoplankton.  When whales die, and sink to the bottom of the ocean, they take their stored carbon with them. Forest elephants in Central Africa browse smaller trees, alleviating competition and allowing surviving trees to grow larger; researchers estimate that loss of elephants has decreased carbon stocks by 7% in their forest ecosystems.  

We do not have the time to ignore biodiversity as we mitadapt or to ignore mitadaptation when we effect biodiversity conservation. Nature-based solutions are also predicated on the notion that attending to functioning ecological communities makes human communities function better, as well.  Finally, and perhaps most importantly, it makes practical and economic sense to promote biodiversity when implementing climate change mitigation and adaptation goals, and vice versa.  If we are to survive this period of rapid ecological transition, we require a cultural paradigm shift where we see ourselves as fundamentally interconnected with the natural world.  The mitadaptation examples above demonstrate ways that our actions, policies, and laws could evolve to reflect and reenforce synergistic, holistic, systems-thinking imaginings.

(Thanks to Donato Catrina, UC Hastings class of 2023, for excellent research assistance.)

- David Takacs, Professor of Law at UC Hastings Law School.

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