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Climate Change 

November 25, 2013

United Nations Climate Change Convention’s 19th Conference

I don’t want to be too cynical about the outcome, but…

(credit D. Horsey)

Image credit

Filed under: Climate Change — Peter @ 7:22 pm

November 18, 2013

Tipping the Biosphere V: Options

This is the fifth and final installment of my essay, Tipping the Biosphere.
Part II.
Part III.
Part IV.

Total primary energy consumption of the world's 10 most populous countries (China, India, United States, Indonesia, Brazil, Pakistan, Nigeria, Bangladesh, Russia, Japan), 2009 (BTU = British thermal unit).

Total primary energy consumption of the world’s 10 most populous countries (China, India, United States, Indonesia, Brazil, Pakistan, Nigeria, Bangladesh, Russia, Japan), 2009 (BTU = British thermal unit).

A great deal of attention is paid to the proximal causes of biosphere degradation, such as climate change, yet mitigating efforts remain largely ineffective. Unfortunately, the proximal causes are not, as argued earlier, the ultimate basis of degradation. Ultimately, the global population will continue growing, and regardless of how resources are consumed in the future, the base level of consumption must increase with population size. Yet, there are reasons to be hopeful if some effort is focused on these ultimate drivers. It is true that little can be done at this point to lower population size, but there is much to be gained by addressing the rate of population growth and rates of resource consumption.

It is unlikely that the global population, projected to reach 10 billion by 2050 [1], will be reduced significantly by any anthropogenic or natural mechanisms. Possibly the only mechanisms are deadly pandemic disease, or very high energy but low frequency physical events, such as asteroid impact. War on a scale matching the damage of such an event is almost unimaginable, the ever-present nuclear threat notwithstanding. Furthermore, predictions of severe food shortages have yet to materialize because of continuing technological innovations, socio-political developments such as better strategies for food security, and the relentless domestication of natural spaces and resources. Growth of the global population will therefore continue into the near future, taking the biosphere ever further into the left half of our catastrophe landscape, and possibly towards a tipping point. The speed at which this happens, however, depends on the rate of population growth, and therein lies some hope. Even as the global population continues to grow, many countries are experiencing low fertility rates, e.g. those in the European Union, where the collective rate is 1.6 [2]. There are economic costs associated with a low fertility rate and aging population, but perhaps those costs can be dealt with far more effectively on the long-term than those resulting on the short-term from an irreversibly devastated biosphere. Moreover, low fertility rates are associated with positive developments in political freedom and stability, individual economic security, higher literacy rates, the extension of basic human rights and equality to women, and access to reproductive education and birth control.

Per capita electricity consumption, United States, 2010. Red – five most highly ranked states (Wyoming, Kentucky, North Dakota, Louisiana, South Carolina), green – five lowest ranked states (California, Hawaii, Rhode Island, New York, Alaska). Florida and Texas are in neither group, but have both high populations and climate extremes.

Per capita electricity consumption, United States, 2010. Red – five most highly ranked states (Wyoming, Kentucky, North Dakota, Louisiana, South Carolina), green – five lowest ranked states (California, Hawaii, Rhode Island, New York, Alaska). Florida and Texas are in neither group, but have both high populations and climate extremes.

The decoupled nature of population size and resource consumption, however, means that slowing population growth will be insufficient if resource consumption continues to grow. There is hope here also though, exemplified by the large variation of consumption rates both among and within nationalities. For example, globally the United States ranks first in per capita energy consumption (i.e. how much energy each individual human uses) (Figure) [3]. Yet, among US states California, the most populous state in the union, has the lowest per capita rate of electricity consumption while Wyoming, with a population 66 times lower than California’s, has the highest rate (Figure) [4]. Climatic differences account for some of this disparity, with Wyoming having amongst the coolest summer and coldest winter temperatures in the US. Climate alone cannot account for all the variance, however, because California also has two of the top 10 hottest major cities in the country, along with other populous states such as Texas and Florida. Neither of the latter states is in the top five when it comes to per capita consumption. On the other hand, other states who are in the top five group, such as Kentucky, do not have particularly extreme climates, nor large populations, and therefore have considerable room for reducing per capita energy consumption rates while maintaining high standards of living.

The global environmental crisis has little precedent in Earth’s history, and none in human history. Burgeoning human population and resource consumption are the driving forces behind the crisis’ many manifestations. There is a real possibility, given the complex nature of the biosphere, of a transition from the planet to which we are accustomed, to one with greatly reduced biodiversity and ecosystem services. The point at which this will occur, the rapidity with which it will proceed, and the exact nature of the new state, are difficult to predict. The best available options are to decrease rates of fertility and consumption, with good evidence that these can be accomplished. Both rates must be reduced, for to do one without the other would take us into undesirable zones of the catastrophe landscape. That is, increasing the population while reducing per capita consumption rates will result in increasingly low and difficult standards of living, a condition already present in the world’s most populous poor nations. Conversely, limiting or reducing population size in order to grow per capita resource consumption, while benefiting an elite individual, would keep a tipping point perpetually looming in the future, nevermind the thorny issue of how populations would be reduced in the first place. Both scenarios are nightmarish worlds, yet the irony is that, given a world with depauperate biodiversity and failing ecosystem services, one of those scenarios would become an eventuality. Hope stems from the fact that there are viable solutions. All that are needed is our collective will and sufficient caring for both the natural and human worlds.

[1] United Nations, Department of Economic and Social Affairs, Population Division. 2011. World Population Prospects: The 2010 Revision, Highlights and Advance Tables.
[2] Eurostat. 2010. Demography Report 2010.
[3] U.S. Energy Information administration.
[4] The California Energy Commission, Energy Almanac.

Filed under: Climate Change — Peter @ 11:25 am

November 8, 2013

Tipping the Biosphere IV: Visualizing a tipping point

This is the fourth installment of my essay, Tipping the Biosphere.
Part II.
Part III.

A "cusp catastrophe manifold" illustrating a model for a biosphere tipping point

Catastrophe landscape describing biosphere state. Human history begins in the upper right region, but is now on either the red or blue trajectories. Alternative trajectories (brown), lead either to the lower right (small population, high resource consumption), or the upper left (high population, low resource consumption).

Much of our understanding of tipping points is captured by Catastrophe Theory, a deep and ominously named mathematical theory. Though complicated, the theory provides us with a useful heuristic device, the catastrophe manifold, for visualizing the manner in which a system will respond to external forces or controls[1]. The surface in the figure, known as a cusp catastrophe, illustrates the behaviour of a system that is capable of a catastrophic state shift when controlled by two parameters. For our case, the system is the biosphere and the controlling factors are population size and resource consumption. The height of the surface indicates the quality of the biosphere, with greater height corresponding to a healthier biosphere. Height, and hence biosphere quality, decrease as either population size or resource consumption increase.

One can imagine the biosphere moving on this surface in response to changes in the controlling factors. Only a small part of the surface has been explored during human civilization’s brief history, and the initial position of the biosphere would have been the upper right corner; small population size and low resource consumption. We have been moving steadily since then toward the lower left corner, of high population size, high resource consumption, and a qualitatively declined biosphere. That trajectory is undesirable because of the unsustainable strain on natural resources, and all the negative effects associated with human over-population and over-crowding. This argument is indisputable, though the potential for decline must be tempered by many uncertainties, including the possibility of innovative technological and socio-political adaptations. Furthermore, the catastrophe model is not necessarily the ”right” model in any precise sense, but its unique contribution that demands attention is illustrated by the folded and creased region of the surface. If future population growth and resource consumption move the biosphere’s state into this region (shown by the red-arrowed trajectory), the transition to an undesirable state will be relatively sudden; the biosphere will have arrived at a tipping point. This is illustrated by the abrupt change in direction of the trajectory. ”Relatively sudden” means that the period of transition between states will be brief relative to the time spent in the current state, i.e. 12,500 years since the last ice age ended. But what does that mean, precisely? Decades? A century? Our understanding of climate and ecological systems suggests a timescale of decades, but the fact is that we simply do not know. There are no numbers on either controlling axis in the figure! In fact, the trajectory could be the blue one, in which case the state transition would be incremental, affording society more time to mitigate and adapt, though whether either would happen is also uncertain. If a tipping point does exist in the global biosphere system, the real question is, what can we do to avoid, or at least forestall, the tip?

[1] Roopnarine, P. D. 2008. Ecological Informatics: Catastrophe Theory. Encyclopedia of Ecology, Elsevier Press. p. 531-536.

Filed under: Climate Change — Peter @ 3:29 pm

September 27, 2013

New IPCC report

IPCC 2013 report

The IPCC’s new summary report has been released: “Climate Change 2013. The physical science basis“. The publication is available for free downloading or online reading. Probably the most significant conclusion of the study is that scientists are 95% certain that human activity is responsible for the ongoing episode of recent global warming. The details of the document cover the mechanics of greenhouse gas-driven warming given updated emissions data, and the physical consequences, including warming air temperatures, changes in precipitation (mostly rainfall), sea level rise, and other ocean changes. The report also explores predicted changes to biogeochemical cycles, the all-important pathways through which living systems interact with, influence and are influenced-by the physical and chemical environments.

So now the real work begins in a sense. Given this state-of-the-art report, it will now be up to biologists, economists, sociologists, policy makers and others to translate these findings and predictions of the physical world into impacts on the living world, including our human society. These will be challenging efforts, but necessary if we are to then move onto the next steps of formulating solutions, both mitigative and adaptive. Further down the road, and of particular personal scientific interest, will be studies to figure out how changes to the living world, both naturally driven and perhaps also based on human decisions, will feed back into the physical world. The work never ends!

Here’s a nice summary and commentary from the BBC: “IPCC climate report: humans ‘dominant cause’ of warming“.

Filed under: Climate Change — Peter @ 6:58 am

September 21, 2013

Overpopulation? No problem!

Giving Out Corn to the People, During a Season of Scarcity.”: Chinese officials engaged in famine relief. Detail of engraving by G. F. Sargent.

I recently wrote a commentary on Erle Ellis’ op-ed in the NY Times, addressing human overpopulation, food, and ecosystems. I found it to be a rather poorly constructed article, and addressed it in my Food Weblog. Here is the full response:
Overpopulation? No Problem!

Filed under: Climate Change — Peter @ 10:29 pm

September 3, 2013

Tipping the Biosphere Part III: A Tipping Point for Earth?

This is the third installment of my essay, Tipping the Biosphere.
Part II.

(Image by Cheng (Lily) Li)

“Tipping point” has become a part of modern jargon, referring to a sudden change in the state of a system (e.g. an explosive disease outbreak) in response to an external driving force (or “control parameter” in scientific jargon). There is a considerable body of mathematics underlying this jargon, and we can identify four key features of systems that possess tipping points. First, the driving force can be applied incrementally over a broad range of intensities and result in little change to the system. This can be caused by a natural resistance of the system to change, or resiliency so that after being disturbed the system returns to its pre-disturbance state. Second, there is a point at which the next incremental change of the controlling parameter results in a significant change in the system’s state. The straw has broken the camel’s back and the system “tipped”. Response to the driving force changed either because the intensity of the driver can now overcome the internal resistance or resiliency of the system, or had eroded it incrementally, setting in motion previously inert or insignificant processes. Alternatively, the intensity of the driver can be reduced to a point where internal processes become more effective controllers, rendering the driver ineffective. Third, the intensity of the disturbance at which the system tips differs according to whether intensity is increasing or decreasing. In other words, if you added 10 kg to tip your scale, you would have to remove more than 10 kg to regain balance! Finally, two similar states can nevertheless be divergent in their responses, i.e. are sensitive to initial conditions.

Tipping points in many physical systems are well understood and find application in physics and engineering. In other real-life situations with apparent tipping points, however, such as disease outbreaks, or socio-political upheavals, analysis is more difficult. Difficulties stem from an incomplete identification and understanding of the driving factors, limits on the precision with which those factors can be measured, and complex interactions among multiple drivers and the system’s state. Therefore, when change occurs, it often surprises.

Why then do some scientists argue that the biosphere is approaching a tipping point? Specifically, why identify population size and resource consumption as controlling parameters? Because the effective drivers that result from those parameters, e.g. climate change and ecosystem disruption, have caused biosphere transitions in the past, and are themselves capable of dramatic transitions. For example, there is considerable concern that the consequences of ongoing global warming will be manifested as sudden shifts in climatic regimes rather than gradual transitions[7]. Climate change in the geologic past altered the biosphere in diverse ways, including extinctions and outbursts of evolutionary diversification. Another agent of ancient biosphere transformation was planetary or ecosystem primary productivity. Primary productivity is the energy converted to food by plants and other photosynthesizers. Large increases of primary production in the past, fertilized by various processes such as volcanism, were associated with increases of biological richness and ecological diversity. Large disruptions or decreases of this energy supply, however, linked to events such as asteroid impacts, climate change and oceanographic changes, are associated with regional to global ecological collapses and extinctions[8]. Humans today utilize or influence 24-41% of global primary production through the agricultural cultivation of a rather low diversity of species and the direct utilization or alteration of productive terrestrial systems[9,10]. In the oceans, where microscopic organisms are responsible for up to 50% of the Earth’s primary production, there is growing concern about the effects of increasing ocean temperatures and acidity. More directly, when we reduce the amount of space available to species or biological communities, or reduce the connectivity among those spaces, the result is extinction or community collapse. Thus, despite difficulties inherent to predicting tipping points in a system as complex as the global biosphere, there is sufficient evidence at both long time scales and small spatial scales that the biosphere is capable of such transitions, and sufficient reason to be concerned. An important question then is, as we increase the amount of the biosphere affected by humans, will local and regional collapses interact synergistically to result in global collapse? Counterintuitively, potential solutions emerge when we acknowledge the fundamental roles of human population size and resource consumption.
[7] Lenton, T. M. et al. 2008. Tipping elements in the Earth’s climate system. Proceedings of the National Academy of Sciences, 105: 1786-1793.
[8] Roopnarine, P. D. 2006. Extinction cascades and catastrophe in ancient food webs. Paleobiology, 32: 1-19.
[9] Haberl, H. et al. 2007. Quantifying and mapping the human appropriation of net primary production in Earth’s terrestrial ecosystems. Proceedings of the National Academy of Sciences, 104: 12942-12947.
[10] Roopnarine, P. D. 2008. Ecological Informatics: Catastrophe Theory. Encyclopedia of Ecology, Elsevier Press. p. 531-536.

Filed under: Climate Change — Peter @ 9:02 pm

August 5, 2013

Tipping the Biosphere, Part II: Transforming the Earth

This is the second installment of my essay, Tipping the Biosphere.


Suzhou (Roopnarine)

The historical and lifetime experiences of humans accustom us to regularities in the Earth’s dynamics; e.g., tides ebb and flow, and species migrate annually. Civilizations, past and present, have always depended on those regularities. Disruptive episodes or events can sometimes be forecast, e.g. quasi­ periodic droughts, or they may come as a surprise, e.g. earthquakes. Our concern about those events depends on their frequencies, intensities, and purely psychological factors [2]. For example, massive earthquakes (moment magnitude 8.0 or greater) occur infrequently in densely populated areas, but past experience at local to regional scales makes them important to humans. Events that transform the entire biosphere, on the other hand, lie outside human historical experience, and our knowledge of them comes from the geological and fossil records. Those ancient events were driven by physical factors, ranging from massive volcanism to asteroid impacts to orbital fluctuations. They also have biological feedbacks, exemplified in the ice ages of the past 2.5 million years, in which the biologically-­based carbon cycle controlled atmospheric levels of the greenhouse gas carbon dioxide. Mass extinctions are commonly associated with those events, such as the end ­Permian extinctions of 251 million years ago, when approximately 90% of Earth’s species became extinct [3] as a consequence of extensive Siberian volcanism, or the end Cretaceous asteroid impact of 65 million years ago, when roughly 70% of species became extinct [4]. The most recent global transformation occurred just 12,500 years ago at the end of the last ice age, when climate change and human expansion (Note: and possibly a meteor impact) caused the extinction of many large terrestrial animals [1]. Natural recurrence of any of those Earth­-transforming events in the near­future is of low probability. For example, eruption of the Toba super­volcano in Sumatra 26,500 years ago, brought our own species to the brink of extinction (Note: but see), but the probability of a similar eruption in the next 50 years is estimated to be 0.1% or less [2].

Today the Earth is undergoing another transformation, with consequences for both biological diversity and human well­-being, but this time humans are the agents of change. The ways in which we are transforming the planet are diverse, including: anthropogenic global warming; landscape alteration, fragmentation and destruction; species over­-exploitation; pollution; and invasive species. Underlying all these factors, however, are two fundamental parameters of modern human society; population size and resource consumption. All other factors stem from the effects of a burgeoning global population and increased resource consumption. Needless to say we must continue to mitigate and perhaps halt our transformation of the atmosphere, species over­-exploitation and landscape destruction, but these will bring temporary reprieves at best. As long as global population and resource consumption continue to increase, their effects will be translated into biosphere­-transforming factors. Complicating the search for, and implementation of solutions are the feedbacks and synergistic relationships among the transforming factors (including population size and resource consumption). For example, clearing land for agriculture to feed a growing population is sometimes followed by a loss of vital ecosystem services, such as clean water, soil conservation and firewood production, prompting further clearing, the concentration of populations into denser collectives, and the importation of basic consumables such as water and fuel. Interestingly, the relationship between population size and resource consumption is a largely independent one! There is of course a base level of resource consumption necessary to sustain a population of any given size, though I suspect that the level is rather low and would not meet everyone’s expectations of a decent standard of living (imagine a gulag). Beyond that base level, resource consumption is mostly a matter of choices, and the biosphere­ transforming choices that we make often either have little to do with population size, or have an indirect connection. One simply looks to history’s record of over-­exploited and exhausted resources, which pre­dates the exponential increase of global population size which began in the 19th century. Plato bemoaned the final deforestation of Attica in the 5th century BCE [5], which fueled Athen’s silver mines. The Atlantic Gray Whale was extinct by the beginning of the 19th century CE after being whaled by coastal communities since at least the 16th century [6].

The relationship between population size and consumption is therefore an irregular one, based as much on socio-­economic context, social norms and societal goals, as it is on need. Our current problems are generated by levels of resource consumption that either remain fixed or grow as population size increases. Drivers of negative biosphere transformation are thus created and exacerbated. The complexity of natural systems, such as climate or ecosystems, as well as the nonlinearity of their internal processes, raises the possibility that any such transformation could come as a tipping point, rather than gradually and incrementally. The irregularity of the population size­-resource consumption relationship, however, also raises hope for avoiding, or at least adapting to, the transformation.


[1] Barnosky, A. et al. 2012. Approaching a state­shift in Earth’s biosphere. Nature 486:52­58.
[2] Smil, V. 2008. Global Catastrophes and Trends. The MIT Press, Cambridge, USA. 307p.
[3] Chen, Z. And M. J. Benton. 2012. The timing and pattern of biotic recovery following the end­ Permian mass extinction. Nature Geoscience, 5: 375­383.
[4] Schulte, P. et al. 2010. The Chicxulub asteroid impact and mass extinction at the Cretaceous­ Paleogene boundary. Science, 327: 1214­1218.
[5] Hughes, J. D. And J. V. Thirgood. 1982. Deforestation, erosion, and forest management in Ancient Greece and Rome. Journal of Forest History, 26: 60­75.
[6] Bryant. P. J. 1995. Dating the remains of gray whales from the eastern North Atlantic. Journal of Mammalogy, 76: 857­861.

Filed under: Climate Change — Peter @ 1:27 pm

July 20, 2013

Tipping the Biosphere, Part I: Introduction

I recently published a chapter in a book, Meer!, edited by Dutch parliamentarian, Marianne Thieme. Here is a summary (translated; my apologies) from the publisher, Uitgeverij Jan van Arkel:

MORE! has become the central theme of our society: more of everything and more than there is. In the last decades of unprecedented prosperity, the belief has taken hold that the growth of our economy is not only boundless, but also a prerequisite for happiness and prosperity. Where economics was once the science of the production and distribution of scarce goods, it has at the end of the 20th century turned into an exclusive focus on money and monetary issues. The systemic crisis that presented itself in 2008 as a banking crisis, is now clearly a monetary crisis and it is clear that we also have the biodiversity crisis, the climate crisis, the world food crisis and other scarcity problems that prosperity and well-being threatening to the core.

The book brought together a number of scientists, and asked us to contribute our views on the current econo-environmental crises facing the world, the sources of the crises, possible outcomes, and potential solutions. I will present an English version of my contribution over the next few posts on this blog. My chapter is entitled, “Tipping the Biosphere”. Here is the Introduction.


Peter D. Roopnarine
Department of Invertebrate Zoology & Geology, California Academy of Sciences, 55 Music Concourse Drive, San Francisco CA 94118 USA

The global biosphere comprises the Earth’s living organisms, their interrelationships, and their ecosystems. Any assessment of the biosphere’s state or condition includes at least the number of species on the planet (richness), their ecological diversities, i.e. the ways in which they make their livings, and the number of ecosystems into which richness and diversity are organized. When considering human well-being, measures of biosphere condition should also include the types and magnitudes of services provided to humans by the biosphere, such as renewable natural resources, and the types and magnitudes of human impacts on the biosphere. The state of the biosphere and human well-being have become inextricably intertwined over the course of human history, both as the ways in which humans use the natural world have become more diverse and increasingly sophisticated, and as the number of humans, all of whom depend ultimately on the biosphere for survival, has increased exponentially. The negative impacts of humans on the biosphere are today evident everywhere, from heavily urbanized areas to remote stretches of the open ocean, and there can be no doubt that we are transforming the planet. Of particular concern to many scientists is the possibility that increasing human pressure on the planet’s natural systems and resources is rapidly transforming it to a state of decreased richness and ecological diversity. A biosphere so transformed would represent a loss of adaptive evolutionary potential, as well as the reduction and loss of ecosystem services and other dependencies to human well-being. Of equal concern is the possibility that the transformation will not unfold smoothly and incrementally, but will instead behave as a tipping point, where the biosphere will transition rapidly between states [1].

[1] Barnosky, A. et al. 2012. Approaching a state-shift in Earth’s biosphere. Nature 486:52-58.

Filed under: Climate Change — Peter @ 11:18 pm

July 1, 2013

Oysters and acidification

From Science Today: “Recently, researchers discovered other effects of acidification on oysters and what the breakdown of the oysters’ calcium carbonate shells could mean for the acidic balance. Science Today sat down with the Academy’s own oyster expert, Dr. Peter Roopnarine, curator and chair of Invertebrate Zoology and Geology, to get some perspective on these recent studies.

Read the rest here!

Filed under: Climate Change — Peter @ 9:22 am

June 14, 2013

Field work after a Mass Extinction

The following is a guest post by Darko D. Cotoras Viedma.

Imagine that somehow you have the chance to travel to the future. A time when you will be alone on this planet and humanity is part of a history that nobody will read. Your mission is to do a biodiversity inventory and try to answer one question: What was the signature of the presence of humans on Earth?

Enclosed on its natural environment the endangered Mauna Kea silversword (Argyroxiphium sandwicense subsp. Sandwicense) is protected with a fence from introduced feral animals. South slope of Mauna Kea. Big Island, Hawai’i.

Enclosed on its natural environment the endangered Mauna Kea silversword (Argyroxiphium sandwicense subsp. Sandwicense) is protected with a fence from introduced feral animals. South slope of Mauna Kea. Big Island, Hawai’i.

Right before that future, humanity never took real responsibility for the environment. It centered its efforts on promoting a strongly industrial development which deepened social inequalities. However, this didn’t affect every aspect of life. The interest in market expansion favored the worldwide access to a whole “family” of products and services associated mostly with entertainment and luxury. Immediate desires related to those things could be satisfied in the same way pretty much anywhere in the world. In that sense the world became more “equal”.

As many science fiction authors predicted, the world became dominated by big corporations. In some places it was easier to get access to their products and services than to any other basic needs. Also the movement of people became extremely easy; the average person lived in three different cities during his/her life and one third of world’s population owned a second house.
Humanity gained complete independence from seasonality and weather. Everybody could get any kind of vegetable or fruit year around. Cities were founded in the middle of the deserts or deep in jungles. But, this way of life couldn’t last for long. When it spread to the entire world it was a matter of a century to reach a point of no return. Hundreds of thousands of years after that event your mission starts.

The first thing you notice is the reduction in species diversity. The long announced “Sixth mass extinction” happened and an important part of the biological patrimony was lost forever. In some cases whole branches of the Tree of Life were lost, while in others only some species. But, what really commanded your attention were the survivors. You expected to find hundreds of different species that evolved from the wide spread agricultural plants and animals, however they were all extinct. The domestication of these organisms made them absolutely dependent on us. On the other hand, other organisms dispersed unintentionally by humans had the distribution pattern you expected. The New World was populated by many new species of grasses coming from Europe, while the islands in Oceania were full of new species of rats, geckos and land snails coming from Africa, South America and Asia.

At the same latitude most of the low elevation environments had a similar biodiversity. The same thing happened in shallow waters in the ocean. Everywhere between 100 meters below to 1,500 meters above sea level, you were able to describe a very well defined biological community, the “Human-impacted community”. Interestingly within this community you found some species originally endemic to those very areas. They are the result of past human conservation efforts. Somehow, by establishing biological interactions with all the rest of introduced species they managed to survive.

Outside of the “Human-impacted community” there is another kind of survival species. Those areas weren’t affected directly by humans, but because of global changes extinctions also occurred. The survival species then had very small population sizes restricted to reduced patches of habitat in comparison to their original distributions.

At some point, standing in the middle of what once was a city you look around and only see an extensive forest, a forest comprised of species that initially were on the sidewalks of the streets or in the backyards of houses. This forest is replicated in all the former cities at this latitude, but now after thousands of years, each one has its own species that evolved from once widely spread ornamental plants.

The world you saw in the future was definitely a different place. Somehow less diverse, somehow more diverse. The same as five times before, life was able to recover from a cataclysmic event. After a period of exponentially rapid change, ecosystems evolved into a new configuration that was stable over units of geologic time.

In a geologic perspective it seems clear that life followed its own course. The main consequences of our activities affected us and the unfortunate species that happened to co-exists with us. The preservation of the environment it is not only a problem of sustainability for our own benefit, it is also a matter of respect for others and I am not talking about other humans.

Darko on Molokai

Darko on Molokai

Darko Cotoras, originally from Chile, is a Ph.D. candidate in the Integrative Biology dept at UC Berkeley. He is interested in the historical processes that shape biodiversity, in particular on insular environments. For his dissertation he is studying the temporal dynamic of the adaptive radiation of an endemic group spiders (genus Tetragnatha) from the Hawaiian archipelago. He has also researched terrestrial invertebrates on the Juan Fernández Islands and Rapa Nui.

Filed under: Climate Change — Peter @ 10:20 pm
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