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The 2020 Call For Code Global Challenge by IBM is calling on developers across the globe to find technological solutions to halt and reverse the impact of Climate Change. To extend support for the initiative, Nature inFocus is publishing a series of Climate Change stories from around the country.


If I told more people about my favourite tree, I would stop getting invited to parties. But surely they would share the sentiment if they could see it. This tree, Dipterocarpus griffithii for the scientifically-inclined and badapatti (big-leaved) gurjan for most who live around it, stands amidst a small clearing tucked inside a side road branching from the main road towards New Wandoor beach in South Andaman. With a pale bark and a head full of dark green leaves, it stands more than 50 metres tall, dwarfing new-growth trees and areca nut palms around it; a lonely giant displaced in time. I wonder if there were other tall gurjan trees around it in the past. 

Dipterocarps are characteristic species of the tallest ('emergent') layer in the lowland evergreen forests of the Andamans. They are also one of the most valuable timber species harvested from the islands. Good soil and high tree density make them grow straight and tall to peek out of the canopy; a logger’s dream. Their seed dispersal also takes advantage of their height; the two-winged fruits (after which they are named) spin, swirl and pirouette down the canopy in dozens, riding the sea winds in January. Few can resist flinging the fallen fruits back into the air for another spin. The trees are mighty, seemingly invincible. My favourite tree has survived forest clearing (for settlement) in the 1980s and the 2004 tsunami. But the threat of climate change is uniquely potent to large evergreen trees like Dipterocarps.

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Dipterocarpus griffithii for the scientifically-inclined and badapatti (big-leaved) gurjan for most who live around it, this is a characteristic species of the tallest layer in the lowland evergreen forests of the Andamans.           Photograph: Krishna Anujan

Global climate is changing rapidly and irreparably. Temperatures are increasing continuously; every year since 2010 has been a new record high. Increased global temperatures are melting glaciers and sea ice, increasing sea levels. Sea level rise, combined with increased sea surface temperatures, alter the interactions between the ocean and the atmosphere. Ocean-atmosphere interactions determine regional climate patterns and so, climate change leads to altered rainfall patterns. Consequently, many areas of the wet tropics now face frequent droughts. Finally, climate change also affects the frequency and intensity of extreme events like tropical cyclones and tsunamis. Besides causing huge losses to human society, climate change alters ecosystems – through pressures on individual species and broader nutrient cycling and related ecosystem processes. 

Many ecologists can almost recite this global understanding of climate change gathered from journal articles and IPCC reports. It also forms the basis of my National Geographic Society-funded research to understand how seedlings grow and establish themselves under different environments to predict the future of forests in the Andaman Islands. In March 2019, my team of undergraduate interns and I began to foster seedlings of different tree species native to the islands, including 150 of gurjan, and measure their growth under different environments and in mixtures with other species. We wanted to see how they would fare when replanted into logged forests. Many gurjan seedlings died in the first dry season, unable to survive dry soils and the unshaded sun. The prognosis for this species did not look good in an altered future. But we were optimistic because the ones that did survive were making disproportionately giant leaves, determined to grow.

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Funded by the National Geographic Society, the team is fostering seedlings of different tree species native to the islands and measuring their growth under different environments and in mixtures with other species.       Photograph: Krishna Anujan

On a field visit to a replanting site in October, a forester asked me earnestly whether climate change will make the islands uninhabitable in the next few decades. The islands were his home for two generations and he had just seen a news report that stated this. I fumbled. Even as climate change formed the backbone of my research question, the immediacy and personal threat to the islands was not obvious to me until then. For a place like the Andamans, climate change is not a distant reality in place and time. It is here and it is now. 

My ignorance was partly because global understanding does not translate easily to local predictions. High-confidence predictions of climate change at the aggregate global scale are made through mathematical models of interactions between the atmosphere and ocean, that smooths over nuances for generality. Local climate is often regulated by a mix of global systems and local factors. And so, when it comes to local predictions, climate models have wide uncertainty blankets, like ‘free size’ clothes.

The IPCC Special Report on Oceans and the Cryosphere notes that since 2006, mean sea level has been rising at 2.5 times the rate of the last century. This is devastating for an island ecosystem with long coastlines and low-lying land, you deduce. This rate is not uniform either and is predicted to be worsened with local disturbances. The last decade of development in the Andamans has seen coastal development, sand mining and reclamation of wetlands, and this has only likely increased the effects of sea-level rise. In the islands, rise in sea level could swallow coastal property, coastal forests and adjoining low-lying evergreen and moist deciduous forests which are at sea level. It could disconnect landmasses now connected by low-lying land bridges, impeding the movement of small reptiles and amphibians. The 2004 tsunami was a landmark event that left lasting impacts on the Andaman archipelago in terms of human and habitat losses. The IPCC report also states that rising sea levels increase the probability of tsunamis. In sum, the islands are predicted to be severely affected by climate change by 2050. And yet, we know little of the details until we build local models to fit. 

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"Post-logging forests may not recover in the same manner and overfished or bleached coral reefs may not bounce back with the same vigour when in adverse climates." Whole stands of trees can be killed by wave action and changing coastlines, like these in the Nicobar Islands. Photograph: Adhith Swaminathan

One thing is certain; the effects of climate change on the environment are insidious and ubiquitous. Global change has the potential to affect every ecosystem – forests, mangroves, littoral forests, coastal wetlands and corals reefs, through warming and inundation. It also amplifies the effects of other local stresses on these ecosystems. Post-logging forests may not recover in the same manner and overfished or bleached coral reefs may not bounce back with the same vigour when in adverse climates. This makes island ecosystems like the Andaman Islands, where many ecosystems exist with close links to each other, especially fragile, through dissonance and imbalances among ecosystems. Moreover, much of the population here lives in close relationship with the environment and natural resources. Forestry, agriculture, fisheries and nature-based tourism are the largest industries in the Andamans currently. The tropical Indian Ocean has reported negative effects on fisheries, habitat services and the neighbouring Pacific Ocean has also reported impacts on tourism. As the climate continues to change, livelihoods in the Andamans are also under threat. 

Under all layers of life in the islands are intangible links to the landscape. The history of the islands’ occupation is riddled with notes on impenetrable forests, labyrinthine mangroves and incurable malaria. Original Great Andamanese place names like Thi-ta-umul (a place with lots of undergrowth, currently called Diglipur) and settler names like Dhani Khadi (a creek of Nypa palms) echo of the habitat they reside in, like ocean sounds inside a shell. Today, one fishes at “the big rock around the bend”, unmarked bus stops are “where the Siris tree was cut last year” or at the “large ficus tree with branches towards the road”. In this landscape, history, linguistics and even economics can be traced back to biogeography.

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"Beyond extinction, ecological grief extends to despair about the inevitability of future change and the resulting intangible loss of intimate knowledge about your landscape." A bleached colony of Acropora sp. coral. Photograph by Vardhan Patankar, courtesy Wikimedia Commons, under the CC-BY-SA-4.0 license.

As our senses of 'normal' erode and habitats get replaced in the Anthropocene, the loss and mourning we experience has been termed 'ecological grief'. Several more of our gurjan seedlings died in the following dry season even as most other species flourished. We now have robust data to make predictions about forest regeneration and this will make for a good model. “Interesting,” I termed it. Because how does one express the emptiness felt when the big rock where you fish is submerged and the tall gurjan has died of drought? Beyond extinction, ecological grief extends to despair about the inevitability of future change and the resulting intangible loss of intimate knowledge about your landscape. When the last gurjan has died and the islands have become uninhabitable, who will remember that there existed a symbiotic mushroom, a local delicacy that grows only next to the roots of this species in the monsoon? We can share condolences, “it is inevitable”, “life will go on”, “cockroaches survive nuclear bombs”. But who wants to live in a world full of just cockroaches? Or as Aldo Leopold more eloquently asked, “Of what avail are a thousand freedoms without a blank spot on the map?”


For many islands like the Andamans, climate change is here and now. Actions and solutions need to be resolute and immediate. If you are a developer interested in helping address some of these challenges, visit the Call For Code website and get started on your idea. Winners will be awarded $200,000, receive open source support from The Linux Foundation, and will get a chance to meet mentors and investors. You will find ample resources and support to see your technology come to life. 


References:

1. IPCC, 2019: Summary for Policymakers. IPCC Special Report on the Ocean and Cryosphere in a Changing Climate

2. State Action Plan for Climate Change, Andaman and Nicobar Islands, 2013

3. Oommen and Ramesh, 2019. Ecology, Economy and Society – the INSEE Journal, Tides of Change in the Andaman and Nicobar Islands

4. Srivastava 2012, Proc. Nat. Acad. Sci. India, Section B, Ecological Threats to and Islands Ecosystem due to Climate Change: The Andamans Experience

5. Pankaj Sekhsaria, 2017, Islands in Flux, Harper Collins Pubishers

6. Cuonsolo and Ellis, 2018, Nature Climate Change, Ecological grief as a mental health response to climate change-related loss