Climate change and the Pacific

In 1999 David Schindler, an ecologist, wrote, “To a patient scientist, the unfolding greenhouse mystery is far more exciting than the plot of the best mystery novel”. I wonder how he would describe the mystery novella today, twenty years later. Once you have read this condensed version of the updated story, you can decide if the mystery has deepened, or has been solved. 

An exciting mystery begins by introducing the foundational characters. Originally there were two such characters in the climate change story. In 1824 Joseph Fourier pioneered our understanding of the role of the atmosphere in warming the Earth. He discovered that something in the atmosphere made the Earth warmer than he had previously calculated. A few decades later, in 1861, John Tyndall identified that “something” as what we now refer to as greenhouse gases – carbon dioxide (CO2), water vapor and hydrocarbon gases such as methane. Tyndall proved these to be extremely efficient absorbers of radiant heat energy, in comparison to the more common constituents of the atmosphere, namely oxygen and nitrogen. Tyndall went on to speculate that changes in the concentration of the former gases could have an impact on the Earth’s climate.

And that’s how the opening lines of the story read for well over 100 years.

The story line had to be rewritten in 2011, when a scholar by the name of Raymond Sorenson published an article which identified a third foundational character. Sorenson highlighted that in 1856, three years prior to Tyndall’s first report, the research findings of Eunice Newton Foote were presented at an annual science meeting in Albany, New York. Not by her, but on her behalf, by a Professor Joseph Henry. In that era it was very unusual for a woman scientist to be given the opportunity to present her own work, let alone publish a paper. As a result, her work is known today only from a journalistic summary published in the annual review of world-wide scientific achievements in 1856.

Eunice Foote was not only a pioneering American scientist but also a well-known inventor and women’s rights campaigner. Sorenson’s summary highlights the significance of the experiments conducted by Foote. Her most notable achievement was to demonstrate enhanced absorption of radiant heat energy by CO2. She also showed the potential for atmospheric warming due to rising CO2 levels. Significantly, this year (2019) is the 200th anniversary of the birth of Eunice Foot.

 

From then and through the first half of the 20th century the prevailing thinking of the scientific and wider community was, in hindsight, overly optimistic. Since there would be only a slow increase in the Earth’s population, the resulting increase in CO2 emissions would also be slow. The consequential warming would be even slower, due to the uptake of both heat and CO2 by the world’s oceans. And, finally, such warming would be overwhelmingly beneficial.

How wrong this proved to be, on all counts.

From the 1950s on there was a flurry of studies, catalysed by the growing realisation of the many widespread and serious consequences of global warming. The far-reaching significance of these findings was facilitated by comprehensive and authoritative assessments conducted by bodies of independent experts, such as the Intergovernmental Panel on Climate Change (IPCC). The IPCC published its first assessment in 1990, and continues to report its findings on a five-yearly cycle.

In 1850 the Earth’s population was around 1.2 billion. It is now over 7.7 billion. This growth, along with industrialisation and increases in per capita production and consumption, has driven the increasing concentration of CO2 and other greenhouse gases in our atmosphere.

While the Earth’s population increased 6.5 times since 1850, global CO? emissions are now over 150 times higher than they were back then. At that time the United Kingdom was the top emitter of CO?, with emissions nearly six times those of the country with the second-highest emissions, the United States. France, Germany and Belgium completed the list of top five emitters. Now China is the world’s largest emitter, followed by the United States, India, Russia and Japan. Significantly, while the United States has ranked as the world’s second-largest emitter from 1850 to today, its emissions have grown almost twice as fast as the increase in global emissions of CO2. Levels of CO2 in the atmosphere are higher than for at least the last 800,000 years, and the rate of increase is unprecedented in the Earth’s history.

As anticipated, at least in qualitative terms, the oceans have indeed absorbed CO2 – around half of the global emissions since 1800. But even this saving grace comes at a cost. The absorption results in ocean acidification, thereby slowing the growth of calcareous organisms such as coral, while also reducing the rate of further CO2 uptake by the oceans.

The oceans have also taken up much of the additional heat initially trapped by the atmosphere. Indeed, more than 90% of the Earth’s energy imbalance between 1971 and 2010 has been stored as heat in the ocean. But once again, this has come at a cost. The additional heat in the ocean caused 40% of the global mean sea-level rise between 1993 to 2010. A warmer ocean further slows the rate of CO2 absorption, seriously impacts marine organisms and ecosystems, and has wider and serious negative consequences for natural and human systems, both terrestrial and marine.

The consequences of atmospheric and oceanic warming and acidification cascade through and impact all terrestrial, oceanic and atmospheric systems. The changes are so pervasive we now use the umbrella term “climate change”, as opposed to the much narrower expression of “global warming”.

The consequences are equally far reaching, and overwhelmingly negative, for natural as well as human systems. This is so for the Blue Pacific, the world’s largest oceanic continent, which is core to the region’s way of life, shaping the cultural, spiritual and historical identity of Pacific peoples as well as the economies of Pacific Island nations and territories. Blue Pacific captures the Pacific’s transformation from Small Island Developing States (SIDS) to Big Ocean Sustainable States (BOSS). They, and indeed the world, have much to lose as the climate changes. Over 50 percent of the world production of tuna is from the western and central Pacific
Ocean. Fish protein makes up 50-90% of animal protein consumption in rural areas of the Pacific, and 40-80% in urban areas. Pacific Ocean-based fishing and tourism alone provide USD 3.3 billion to the economies of Pacific Island countries and territories, amounting to 10.5% of regional GDP. More specifically, Melanesia’s ocean economy has an estimated worth of USD 548 billion, or USD 5.4 billion annually.

But studies suggest that by 2050 there will be a 20% decline in coral reef fish production in some Pacific Island countries. For 75% of Pacific Island countries and territories coastal fisheries will fail to meet food security needs by 2030, due to a combination of population growth (exacerbating unsustainable extraction), climate change and inadequate national distribution networks. Moreover, nine of seventeen Pacific Island countries and territories could experience declines of over 50% in maximum catch potential by 2100.

When using hindsight to provide foresight it is useful to add insight as an intermediate step. This framing of the climate change story is illustrated by way of two examples of great importance to the Pacific Islands region.

 

Hindsight tells us that coral reefs are capable of growing vertically at rates faster than those projected for sea-level rise this century. They have survived both higher sea levels and high rates of sea-level rise in the past. But insight reminds us that these capabilities are severely compromised if the reef is unhealthy, for example, due to high pollution loads from land-based sources of pollution, physical damage caused by snorkelers, divers and boat operators, or because of coral bleaching and ocean acidification. Foresight tells us that with 1.5°C of global warming, the ambitious target in the Paris Agreement, the Pacific region is facing a loss of 70– 90% of reef-building corals compared to today. With 2°C of global warming 99% of the Pacific’s corals will be lost. The demise of the corals is not just because of the synergistic effects of increases in ocean temperature and ocean acidification. These combine with local threats such as sedimentation, nutrient enrichment, disease, over-exploitation and physical damage. Pacific nations and territories can do little other than lobby others to keep global emissions below the 1.5°C target, and hence limit the rate of increase in ocean temperatures and acidification. But they can do much to prevent the local threats to their coastal ecosystems. 

The second example concerns the future habitability of Pacific islands. This is an equally important issue, but it is also highly contentious, scientifically and politically. Recently we have seen in highly reputable scientific journals papers with titles such as “Most atolls will be uninhabitable by the mid-21st century because of sea-level rise exacerbating wave-driven flooding”. Despite being a much more balanced assessment, the paper with the title “Patterns of island change and persistence offer alternate adaptation pathways for atoll nations” still attracted the ire of some Pacific politicians. A major tension exists between those whose agendas are served by studies which invoke the likelihood of climate-induced migration, and those who recognize the strong and enduring relationship that Pacific Islanders have with their land. For the latter, any talk about forced migration is an anathema.

Hindsight informs us that over recent decades, and despite the Pacific experiencing some of the highest rates of sea-level rise globally, over threequarters of the 394 Pacific atoll islands included in the study were stable in area. Importantly, nearly 20% of the islands increased in size, usually due to a combination of natural and human factors. The areas of less than 10% of the islands decreased in size. The finding that atoll islands affected by rapid sea-level rise did not show a distinct behaviour compared to other atoll islands is of even greater significance.

Recent physical modelling experiments of a reef island add credence to the above findings. The experiments demonstrated that overwash processes provide a mechanism to build and maintain the freeboard of such islands above sea level. Thus these islands have the capability to respond to rising sea level, through island accretion.

The above findings can be complemented by several important insights. The coastal areas of high islands, where people and built assets are usually concentrated, face levels of risk similar to those of atoll islands. Land tenure, infrastructure and other land uses limit the option to retreat in the face of sea-level rise, more damaging storm surges and other coastal hazards. And we all need to be reminded that there are multiple determinants of atoll and high island habitability in the longer term, not just sea-level rise.

In response, the Pacific is demonstrating considerable foresight. For example, the Framework for Resilient Development in the Pacific was endorsed by Pacific Leaders in 2016, and came into effect at the beginning of 2017. The Framework is a global first, where the Pacific seeks to reduce exposure to climate and disaster risk, support low carbon development and improve disaster response and reconstruction. It reflects an understanding of the need to manage climate and disaster risks as an integral part of development. The Framework promotes a “development first” approach, where the desired development outcomes are identified first, and then assessed to determine how climate and disaster risks may affect their achievement. As a result, identification and prioritization of investments relate to the overarching goal of resilient development, where the two goals of sustainable development and building resilience are achieved through a joint approach.

The end of this climate change story lacks a dramatic climax worthy of a mystery novel, but it does give cause for reflection. A key message is the importance of not oversimplifying, or excessively politicizing, the climate and related challenges facing Pacific Island countries and territories. Some have described climate change, and especially sea-level rise, as an “existential threat” to the region, creating “climate refugees” and the need for “migration with dignity”. But as new scientific evidence comes to hand, resulting in fresh and widespread understanding, such rhetoric and policy is increasingly giving way to that of “stay and fight”. This involves relying on achieving more resilient development, including through adaptation and emissions mitigation efforts.

Does all this mean that, 20 years on, Schindler would have a different view of the “unfolding greenhouse mystery”? This condensed version of the story would suggest not.

While the plot has changed from solving the science to clarifying island and human futures, multiple objectives, tensions and maneuvering are enduring features of the climate change story