Rio + 20 in Nature

In the run up to the Rio+20 conference, the June 6 issue of Nature put together a fascinating set of articles assessing the current state of knowledge on the two issues that dominated the original Rio agenda: biodiversity and climate change.



1) In "Biodiversity and its Impact on Humanity" Cardinale et.al. review current understanding about the role of biodiversity in relation to ecosystem functioning and the provision of ecosystem services. Key findings re: ecosystem functioning:

• There is now unequivocal evidence that biodiversity loss reduces the efficiency by which ecological communities capture biologically essential resources, produce biomass, decompose and recycle biologically essential nutrients.
• There is mounting evidence that biodiversity increases the stability of ecosystem functions through time.
• The impact of biodiversity on any single ecosystem process is nonlinear and saturating, such that change accelerates as biodiversity loss increases.
• Diverse communities are more productive because they contain key species that have a large influence on productivity, and differences in functional traits among organisms increase total resource capture.
• Loss of diversity across trophic levels has the potential to influence ecosystem functions even more strongly than diversity loss within trophic levels.
• Functional traits of organisms have large impacts on the magnitude of ecosystem functions, which give rise to a wide range of plausible impacts of extinction on ecosystem function.
• The impacts of diversity loss on ecological processes might be sufficiently large to rival the impacts of many other global drivers of environmental change.
• Diversity effects grow stronger with time, and may increase at larger spatial scales.
• Maintaining multiple ecosystem processes at multiple places and times requires higher levels of biodiversity than does a single process at a single place and time.
• The ecological consequences of biodiversity loss can be predicted from evolutionary history.

The findings re: ecosystem services were more tentative:

• There is now sufficient evidence that biodiversity per se either directly influences (experimental evidence) or is strongly correlated with (observational evidence) certain provisioning and regulating services.... For provisioning services, data show that (1) intraspecific genetic diversity increases the yield of commercial crops; (2) tree species diversity enhances production of wood in plantations;
  (3) plant species diversity in grasslands enhances the production of fodder; and (4) increasing diversity of fish is associated with greater stability of fisheries yields. For regulating processes and services, (1) increasing plant biodiversity increases resistance to invasion by exotic plants; (2) plant pathogens, such as fungal and viral infections, are less prevalent in more diverse plant communities; (3) plant species diversity increases above ground carbon sequestration through enhanced biomass
  production (but see statement 2 concerning long-term carbon storage); and (4) nutrient mineralization and soil organic matter increase with plant richness.
• For many of the ecosystem services reviewed, the evidence for effects of biodiversity is mixed, and the contribution of biodiversity per se to the service is less well defined.
• For many services, there are insufficient data to evaluate the relationship between biodiversity and the service.
• For a small number of ecosystem services, current evidence for the impact of biodiversity runs counter to expectations.

2) In "A global synthesis reveals biodiversity loss as a major driver of ecosystem change" Hooper, et. al. summarize evidence showing that extinctions are altering key processes important to the productivity and sustainability of Earth’s ecosystems

3) In "Approaching a state shift in Earth’s biosphere" Barnosky et. al. review the basics of state shift theory, review the evidence relating to past planetary-scale critical transitions and state shifts, and examine research related to a number of contemporary global-scale forcing mechanisms: human population growth with attendant resource consumption, habitat transformation and fragmentation, energy production and consumption, and climate change.

4) The political/policy pieces -- documenting how poorly nations have done in realizing their 1992 promises and describing developments that hold out the potential for a more optimistic future -- are worth checking out as well, but they are significantly less interesting than the articles summarizing current scientific knowledge.

Limits to Growth Revisited

It was forty years ago today,
Donella Meadows taught the band to play
They've been going in and out of style
But they're guaranteed to raise a smile.
So may I introduce to you
The act you've known for all these years,
Donella Meadows' Limits to Growth.


.... Well, truthfully, it was forty years ago on March 1, but close enough.

This book, which sold over ten million copies in various languages, was one of the earliest scholarly works to recognize that the world was fast approaching its sustainable limits. Forty years later, the planet continues to face many of the same economic, social, and environmental challenges as when the book was first published. Suitably, the event has spawned a number of retrospectives. The most fulsome occurred at the Smithsonian where the Club of Rome sponsored Perspectives on Limits to Growth: Challenges to Building a Sustainable Planet. Among the presentations were the following:

• Dennis Meadows It is too late for sustainable development
• Jørgen Randers Lessons of forty years of promoting limits to growth
• Lester Brown World on the Edge
• Doug Erwin Biodiversity: past, present and future
• Richard Alley Climate change and energy; challenges and opportunities
• Neva Goodwin Labor’s declining share and future quality of life
• Panel discussion moderated by Eva Pell, Under Secretary for Science, Smithsonian Institution 

The full nine hour program -- including 10 minutes watching the audience mill about before the first presentation -- is archived at the above link.

For those who would like their celebration served up in a more time efficient manner, journey on over to Resilience Science where Garry Peterson has two interesting posts: Forty Years of Limits to Growth and Paul Gilding talks about Limits to Growth which includes Gilding's recent Ted Talk.

Systems: Economic and Ecological

Two items worth contemplating:

1. Simon Johnson in The Libertarian and the Lobbyists explores the role of government regulation (or lack thereof) on the recent financial crash. Of particular interest is the discussion of the findings from two recent IMF reports by Prachi Mishra analyzing lobbying practices in the US.
   

   Legislators, of course, have different preferences about what kinds of laws to support, which can make it hard to study mechanisms of political influence precisely. But Igan and Mishra approach the problem in a clever way – they look for instances when elected officials switched their position on legislative proposals that surfaced more than once. And they devote a lot of effort to figuring out what caused this switch. ...
   A big increase in lobbying expenditures helps to persuade legislators to switch their votes. And “whether any of the lobbyists working on a bill also worked for a legislator in the past sways the stance on that bill in favor of deregulation.” It is deregulation, of course, that financial firms want – fewer rules and less oversight of any kind. And it really is all about whom you know, and how you know them. In particular, your value as a lobbyist seems to depend very highly on whom you worked with in the past. Igan and Mishra find “spending an extra dollar is almost twice as effective in switching a legislator’s position if the lobbyist is connected to the legislator compared to the case where the lobbyist is unconnected.” ...
   Essentially, financial firms have been buying the right to take on more risk. When things go well, executives in these firms get the upside – mostly in terms of immediate compensation, because few executives are compensated on the basis of risk-adjusted returns. That means that when the risks materialize and the firms suffer losses, the costs fall on taxpayers.
   Ron Paul is right to point to imbalances of power and massive distortions within the financial sector. He is also correct that many government policies favor relatively few big firms – and favor them in a way that encourages excessive and dangerous risk-taking.
   But Paul and others are wrong to argue that the government is the ultimate cause of all financial evil. Executives in financial firms want to take big risks. They like arrangements under which they win even when they lose.
   Big financial firms can more readily buy the necessary political protection (in the form of deregulation), enabling them to become even bigger and more dangerous. This incentive structure has only become more extreme since the financial crisis of 2008.

2. Erle Ellis describes the findings of his most recent publication, All is Not Lost: Plant Biodiversity in the Anthropocene, as:
   

   the first spatially explicit global assessment of contemporary patterns of terrestrial plant biodiversity (native loss + exotic species gain) at regional landscape scales.The main result: humans have caused a net increase in plant species richness across two-thirds of the terrestrial biosphere, mostly by facilitating species invasions. In most regional landscapes, native species losses were significantly lower than exotic species gains, with agriculture species causing minor increases, but ornamental species sometimes play a large role that is still hard to assess.

   
   While I'm not convinced Ellis's focus on the shift from biomes to anthromes captures the most fundamental characteristics of the Anthropocene, the work is both provocative and, as a result of his heavy use of maps, visually interesting. A number of relevant links are contained in this post by Andrew Revkin.

GM Foods and Resilience Thinking

The National Academies of Science just released their first systematic assessment of genetically modified crops Impact of Genetically Engineered Crops on Farm Sustainability in the United States. Here is a brief description of the report:

Since genetically engineered (GE) crops were introduced in 1996, their use in the United States has grown rapidly, accounting for 80-90 percent of soybean, corn, and cotton acreage in 2009. To date, crops with traits that provide resistance to some herbicides and to specific insect pests have benefited adopting farmers by reducing crop losses to insect damage, by increasing flexibility in time management, and by facilitating the use of more environmentally friendly pesticides and tillage practices. However, excessive reliance on a single technology combined with a lack of diverse farming practices could undermine the economic and environmental gains from these GE crops. Other challenges could hinder the application of the technology to a broader spectrum of crops and uses.

Several reports from the National Research Council have addressed the effects of GE crops on the environment and on human health. However, The Impact of Genetically Engineered Crops on Farm Sustainability in the United States is the first comprehensive assessment of the environmental, economic, and social impacts of the GE-crop revolution on U.S. farms. It addresses how GE crops have affected U.S. farmers, both adopters and nonadopters of the technology, their incomes, agronomic practices, production decisions, environmental resources, and personal well-being. The book offers several new findings and four recommendations that could be useful to farmers, industry, science organizations, policy makers, and others in government agencies.

It is interesting that a report which is generally supportive of the productivity gains that GM crops have provided is highly critical of those same crops from an ecological sociology perspective. Specifically, there is a concern with a) the tendency toward homogeneity (i.e., monocrops) and the resulting lack of resilience in the agricultural ecosystems and b) the emergence of glyphosate resistant diseases due to the wide spread use of Round-up (a glyphosate based herbicide) in combination with Monsanto's Round-up ready GM seeds. The latter development leads farmers to use additional, even more toxic chemicals, to kill off the unwanted weeds.

Homogenization of America

Diversity, whether social or ecological, increases resilience. When it is only this far between McDonald's restaurants in the US, one has to wonder how diversity is fairing! The greatest distance between 2 McDonald's is 107 miles in South Dakota.

Social and Natural Systems in the Decline of North America's Megafauna

One of the most striking characteristics of humans is that we are adaptive generalists. Unlike most species, which are adapted to specific ecological niches, humans have radiated out to populate virtually every land-based ecosystem on the planet. We can do this because we build shelters, transport food and otherwise make arrangements for the necessities of life in those parts of the globe that would otherwise be inhospitable.

It is this capacity, the ability to transform situations to meet our needs, that lies at the root of the interconnection between social and natural systems. The most obvious example of this interconnection is climate change, where humans are pumping the carbon stored in the ground as fossil fuels into the atmosphere and, hence, fundamentally altering both atmospheric chemistry and the global climate.

But what lies at the root of this human capacity? The standard answer is technology. Through technology we transcend the limitations and constraints placed on other species. But a recent article by Christopher Johnson in Science (Science 20 November 2009: Vol. 326. no. 5956, pp. 1072 - 1073) detailing the process of magafaunal decline in North America casts doubt on this account. Here is the story in brief:

Twenty thousand years ago, North America had a more impressive array of big mammals than Africa does today; by 10,000 years ago, 34 genera of these mammals were gone, including the 10 species that weighed more than a ton. Many other drastic changes occurred in this interval, all of which have been advocated as possible causes of megafaunal extinction. The climate flipped from cold to warm, then back to cold in a 1000-year chill (the Younger Dryas), before rapidly rewarming. There were more, larger fires, and the structure and species composition of vegetation changed drastically. People arrived, and the Clovis culture—with a characteristic style of beautifully crafted stone spear points—flourished for less than 1000 years. Some scientists have argued that an extraterrestrial object struck Earth ~13,000 years ago, triggering the Younger Dryas, starting fires, killing the megafauna, and putting an end to the Clovis culture. ....

What about people? It has long been argued that Clovis artifacts signal the first arrival of people in North America south of the boreal ice sheets and that the Clovis people were specialized big-mammal hunters who caused a crash of megafaunal populations from prehuman abundance to extinction within a few hundred years. This “blitzkrieg” scenario is supported by the fact that terminal dates on megafaunal fossils range from 13,300 to 12,900 years ago, which coincides almost exactly with the Clovis period. But the new data show that the megafaunal decline had begun more than a thousand years earlier. If people were responsible for that decline, they must have been pre-Clovis settlers. The existence of such people has been controversial, but archaeological evidence is slowly coming to light and is consistent with their arrival around the beginning of the megafaunal decline. It is beginning to look as if the greater part of that decline was driven by hunters who were neither numerous nor highly specialized for big-game hunting. Clovis technology may have been a feature of the endgame, possibly reflecting an intensified hunting strategy that developed once megafauna had become rare, possibly wary, and harder to hunt. ...

Before 14,800 years ago, the environment around the site studied by Gill et al. was an open savanna or parkland, probably with scattered spruce and rare broad-leaved trees growing over a short grass-dominated pasture, and almost no fi re. As the megafauna declined, woody biomass increased, mainly by growth of broad-leaved trees that had presumably been suppressed by the large herbivores. The result was a transitory spruce/broadleaf woodland, the like of which does not exist today. Big fires broke out ~14,000 years ago, and for the next few thousand years, major fires returned every few centuries. These changes were widespread: Fire increased throughout North America ~14,000 years ago, and the transitory “no-analog” woodland extended over a vast area.

In short, we begin with an ecosystem dominated by open savanna and numerous species of megafauna. Humans arrive, and apparently without the aid of significant technology, kill off the majority of the megafauna thus setting loose a cascade of ecological changes that ultimately result in the replacement of the savanna by a "no-analog" woodland. Thus we have a clear, early example of the interconnection of social and natural systems, but one that seems not to implicate technology as the fundamental driver.

Organic Farming in the US

The New York Times took 2007 USDA data and mapped the location of all farms and of organic ones. They noted:

"The map of organic farms in the United States is clustered into a few geographic centers, a strikingly different pattern than the map of all farms, which spreads densely over many regions, breaking only for the Rockies and Western deserts.

Areas in the Northeast and Northwest have many small organic farms that sell produce directly to consumers. Large organic farms, which some critics call organic agribusiness, have flourished in California.

The largest organic markets by far are for vegetables, fruit and dairy products, according to Catherine Greene, an economist at the Agriculture Department.

Organic vegetables now account for 5 percent of all vegetable sales; organic dairies, which are the fastest-growing sector, now produce 1 percent of the nation’s milk."