Category Archives: Peer Reviewed Article Review

“blue carbon”

This article in Ecological Economics is about carbon sequestration in “mangrove forests, seagrass meadows, and tidal salt marshes”, and policy and market mechanisms that can help make this happen. To me carbon sequestration is not the only or the primary reason to try to conserve these ecosystems, but I will certainly support it if it gets the job done. Plus if we can come up with hard-nosed market-based approaches that actually work, we can apply them to conservation and restoration of a whole range of ecosystems.

Blue carbon – the carbon stored and sequestered in mangrove forests, seagrass meadows, and tidal salt marshes – is considered a cost-effective means to achieve positive climate change mitigation and adaptation outcomes. Blue carbon is therefore of considerable interest to the scientific and policy communities, and is frequently discussed in relation to carbon markets and climate finance opportunities. This paper identifies peer-reviewed and ‘gray literature’ documents that discuss blue carbon in the context of finance and market mechanisms. The document set is analyzed both quantitatively and qualitatively, and the principal scientific, economic, regulatory, social, and management issues that emerge are discussed. The study reveals that (1) the blue carbon literature is dominated by technical and policy commentary, with a dearth of research into practical social considerations and a stark absence of private sector perspectives; (2) there is confusion over the nature and role of important concepts including private and public sector finance and instruments; and (3) understanding of the important issues of investment priorities and risk considerations is also limited. This paper therefore identifies gaps in the blue carbon literature, clarifies critical concepts and issues, and proposes novel pathways for blue carbon research and project development.

Integrating the planetary boundaries and global catastrophic risk paradigms

I think this article in Ecological Economics gets at a very important idea. There are planetary boundaries we are at risk of exceeding, most obviously the ability of the atmosphere and oceans to absorb and hold greenhouse gas emissions before reaching some catastrophic tipping point. Then there are catastrophic risks that come out of left field every once in a while, like war, plague, accidents, and asteroid strikes. Since our attention span and ability to respond seems to be severely limited, we really need to understand which of these risks are the most likely and the most consequential, so we know where to focus our efforts.

Planetary boundaries (PBs) and global catastrophic risk (GCR) have emerged in recent years as important paradigms for understanding and addressing global threats to humanity and the environment. This article compares the PBs and GCR paradigms and integrates them into a unified PBs-GCR conceptual framework, which we call Boundary Risk for Humanity and Nature (BRIHN). PBs emphasizes global environmental threats, whereas GCR emphasizes threats to human civilization. Both paradigms rate their global threats as top priorities for humanity but lack precision on key aspects of the impacts of the threats. Our integrated BRIHN framework combines elements from both paradigms’ treatments of uncertainty and impacts. The BRIHN framework offers PBs a means of handling human impacts and offers GCR a theoretically precise definition of global catastrophe. The BRIHN framework also offers a concise stage for telling a stylized version of the story of humanity and nature co-evolving from the distant past to the present to multiple possible futures. The BRIHN framework is illustrated using the case of disruptions to the global phosphorus biogeochemical cycle.

you know nothing, snow

From Wired Science:

The western United States is undergoing a major shift in precipitation patterns. Large swaths of the West that have historically been dominated by snow in the winter months are starting to see a lot more rain instead. A new study that maps out the predominant form of precipitation shows that this trend could result in an average reduction in snow-dominated area of around 30 percent by the middle of this century.

The western US depends heavily on snowpack to sustain its water supply through the dry summertime, but the new research, published in Geophysical Research Letters in July, suggests this may have to change.

Hmm…here’s the abstract of the paper…not quite so sensational sounding although it still clearly says there is going to be a lot less snow:

This approach identifies areas most likely to undergo precipitation phase change over the next half century. At broad scales, these projections indicate an average 30% decrease in areal extent of winter wet-day temperatures conducive to snowfall over the western United States.

alternative energy

This article (in the descriptively name journal Energy) describes how California could move to an all-renewable energy future, then tries to put an economic value on that. It is always the link between air pollution and health that surprises me. Why don’t people get more upset that power plants and vehicle exhaust are literally taking years off all our lives when there are other alternatives out there?

This study presents a roadmap for converting California’s all-purpose (electricity, transportation, heating/cooling, and industry) energy infrastructure to one derived entirely from wind, water, and sunlight (WWS) generating electricity and electrolytic hydrogen. California’s available WWS resources are first evaluated. A mix of WWS generators is then proposed to match projected 2050 electric power demand after all sectors have been electrified. The plan contemplates all new energy from WWS by 2020, 80–85% of existing energy converted by 2030, and 100% by 2050. Electrification plus modest efficiency measures may reduce California’s end-use power demand ∼44% and stabilize energy prices since WWS fuel costs are zero. Several methods discussed should help generation to match demand. A complete conversion in California by 2050 is estimated to create ∼220,000 more 40-year jobs than lost, eliminate ∼12,500 (3800–23,200) state air-pollution premature mortalities/yr, avoid $103 (31–232) billion/yr in health costs, representing 4.9 (1.5–11.2)% of California’s 2012 gross domestic product, and reduce California’s 2050 global climate cost contribution by $48 billion/yr. The California air-pollution health plus global climate cost benefits from eliminating California emissions could equal the $1.1 trillion installation cost of 603 GW of new power needed for a 100% all-purpose WWS system within ∼7 (4–14) years.

please remind me, what are patents for again?

Okay, maybe so-called intellectual property rights encourage innovation in some industries sometimes. But the evidence shows that they sometimes do the exact opposite, especially if taken to the extreme. This is the abstract of a working paper from the National Bureau of Economic Research:

Cumulative innovation is central to economic growth. Do patent rights facilitate or impede follow-on innovation? We study the causal effect of removing patent rights by court invalidation on subsequent research related to the focal patent, as measured by later citations. We exploit random allocation of judges at the U.S. Court of Appeals for the Federal Circuit to control for endogeneity of patent invalidation. Patent invalidation leads to a 50 percent increase in citations to the focal patent, on average, but the impact is heterogeneous and depends on characteristics of the bargaining environment. Patent rights block downstream innovation in computers, electronics and medical instruments, but not in drugs, chemicals or mechanical technologies. Moreover, the effect is entirely driven by invalidation of patents owned by large patentees that triggers more follow-on innovation by small firms.

microbial life on Mars

Here is some more evidence from the journal Geology that microbial life may exist or once have existed on Mars.

Depletion of phosphorus, vesicular structure, and replacive gypsic horizons of these Martian paleosols are features of habitable microbial earth soils on Earth, and encourage further search for definitive evidence of early life on Mars.

I’m interested in the question of whether life on Earth is truly alone in the universe. If we find just one bacterial cell on another planet, and as long as we don’t think that cell came from Earth or is an ancestor of life on Earth, the question will have been answered. If we can find life just one other place, then it will be likely that there is life all over the place.

connectivity and corridors

From Conservation Biology, here’s an article on connectivity and movement corridor models for wildlife:

Habitat corridors are important tools for maintaining connectivity in increasingly fragmented landscapes, but generally they have been considered in single-species approaches. Corridors intended to facilitate the movement of multiple species could increase persistence of entire communities, but at the likely cost of being less efficient for any given species than a corridor intended specifically for that species. There have been few tests of the trade-offs between single- and multispecies corridor approaches. We assessed single-species and multispecies habitat corridors for 5 threatened mammal species in tropical forests of Borneo. We generated maps of the cost of movement across the landscape for each species based on the species’ local abundance as estimated through hierarchical modeling of camera-trap data with biophysical and anthropogenic covariates. Elevation influenced local abundance of banded civets (Hemigalus derbyanus) and sun bears (Helarctos malayanus). Increased road density was associated with lower local abundance of Sunda clouded leopards (Neofelis diardi) and higher local abundance of sambar deer (Rusa unicolor). Pig-tailed macaque (Macaca nemestrina) local abundance was lower in recently logged areas. An all-species-combined connectivity scenario with least-cost paths and 1 km buffers generated total movement costs that were 27% and 23% higher for banded civets and clouded leopards, respectively, than the connectivity scenarios for those species individually. A carnivore multispecies connectivity scenario, however, increased movement cost by 2% for banded civets and clouded leopards. Likewise, an herbivore multispecies scenario provided more effective connectivity than the all-species-combined scenario for sambar and macaques. We suggest that multispecies habitat connectivity plans be tailored to groups of ecologically similar, disturbance-sensitive species to maximize their effectiveness.

informal economies

I’m somewhat interested in the idea of informal economies. According to this paper from the National Bureau of Economic Research, economists tend to think they’re bad – either a cause of poverty and slow development, or a symptom of it:

We establish five facts about the informal economy in developing countries. First, it is huge, reaching about half of the total in the poorest countries. Second, it has extremely low productivity compared to the formal economy: informal firms are typically small, inefficient, and run by poorly educated entrepreneurs. Third, although avoidance of taxes and regulations is an important reason for informality, the productivity of informal firms is too low for them to thrive in the formal sector. Lowering registration costs neither brings many informal firms into the formal sector, nor unleashes economic growth. Fourth, the informal economy is largely disconnected from the formal economy. Informal firms rarely transition to formality, and continue their existence, often for years or even decades, without much growth or improvement. Fifth, as countries grow and develop, the informal economy eventually shrinks, and the formal economy comes to dominate economic life. These five facts are most consistent with dual models of informality and economic development.

I’ve never bought into the idea that informal economies are 100% bad. I’ve been very lucky to spend some time in central Thailand, right on the edge between a rural and urban area, and to experience a mix of the informal and formal economies. It makes perfect sense that higher-tech sectors like mining, manufacturing, banking, and so forth are run by efficient, formal, corporations. But lower-tech service sectors provide a chance for “poorly educated entrepreneurs” (a pretty condescending term, actually) to provide everyday goods and services to each other at low cost and practically no overhead. Why is it “efficient” to pay $10 for a tasteless corporate meal at the mall, with most of that money going to pay rent to a real estate corporation and its army of lawyers, accountants, human resourcers, and insurance agents, plus the gas and wasted time to get there, vs. $2 for a tastier meal from a neighborhood entrepreneur? When you stop and chat with your neighbor, that’s culture and social capital, not “inefficiency”. And when something bad happens, you and the neighbor are going to lean on each other for help, not the lawyers and accountants working for the faceless corporation that runs the mall.

green roofs

Green roofs are still pretty expensive and not all that common, at least in North America. But here’s a study in Ecological Engineering where they turned out to work better than people thought in Hong Kong, a humid subtropical area.

Urbanization replaces permeable surfaces with relatively impervious ones to intensify mass and temporal response of stormwater runoff. Under heavy rainfalls, urban runoff could impose tremendous stress on the drainage systems, contributing to combined sewer overflow and flooding. Green roof offers an on-site source-reduction sustainable stormwater management measure that mimics pre-development hydrologic functions. It can retain and detain stormwater as well as delay and suppress peak discharge. However, previous studies were conducted mainly outside the tropics. Since green-roof hydrologic performance can be notably influenced by local meteorological conditions, dedicated investigation in the tropics are necessary. Moreover, substrate depth has long been regarded as an influential factor in green-roof stormwater retention, but recent findings have implicated that such relationship may be more complex. This study (1) evaluates green roof stormwater mitigation performance and potentials in humid-subtropical Hong Kong; and (2) investigates systematically the effect of substrate depth and addition of rockwool, a high water-retention growth medium, on quantitative performance. Using multiple 1.1-m2 raised green-roof platforms placed on an urban rooftop, the effect of four substrate-depth treatments on stormwater mitigation performance was examined over a 10-month study period. The results show that, while the retention under Hong Kong’s frequent and heavy rainfall regime seems to be less effective, remarkable peak reduction and peak delay were evidently expressed even when the green-roof systems have reached full moisture-storage capacity. No statistical significance was found between treatments, despite the slightly higher mean performance of the 80-mm soil substrate. Satisfactory peak performance of the 40-mm soil substrate implies that a thin substrate can provide effective peak mitigation, especially if building loads are of concern. Extensive green roof remains as a promising alternative mitigation strategy to urban stormwater management in Hong Kong with potential application to other tropical areas.

Part of me doesn’t like using an inorganic material like rockwool. But if somebody comes up with a simple, cheap material that we can practically just staple or spray on to roofs in urban areas, it could be a quick way to restore a lot of hydrologic function – retention, evaporation, peak flow reduction, and cooling – in urban areas. It could be a transitional step on our way to restoring both hydrologic and ecological functions together – ideally we would want to capture that water and use it to grow something of use to either people or wildlife or both. But we are far from ideal today, so I’m all for some smaller steps in the right direction.

 

functional urban streams

If you want a functional urban aquatic ecosystem, you don’t get it just through half-hearted management measures in the area draining to the stream. You have to get in there and make a functional ecosystem, and then you might be able to protect and sustain it by managing the watershed better. The article in Restoration Ecology looks at a range of numbers from the literature that make the case pretty well:

Urban development is a leading cause of stream impairment that reduces biodiversity and negatively affects ecosystem processes and habitat. Out-of-stream restoration practices, such as stormwater ponds, created wetlands, and restored riparian vegetation, are increasingly implemented as management strategies to mitigate impacts. However, uncertainty exists regarding how effectively they improve downstream ecosystems because monitoring is uncommon and results are typically reported on a case-by-case basis. We conducted a meta-analysis of literature and used response ratios to quantify how downstream ecosystems change in response to watershed development and to out-of-stream restoration. Biodiversity in unrestored urban streams was 47% less than that in reference streams, and ecological communities, habitat, and rates of nutrient cycling were negatively affected as well. Mean measures of ecosystem attributes in restored streams were significantly greater than, and 156% of, those in unrestored urban streams. Measures of biodiversity in restored streams were 132% of those in unrestored urban streams, and indices of biotic condition, community structure, and nutrient cycling significantly improved. However, ecosystem attributes and biodiversity at restored sites were significantly less than, and only 60% and 45% of, those in reference streams, respectively. Out-of-stream management practices improved ecological conditions in urban streams but still failed to restore reference stream conditions. Despite statistically significant improvements, assessing restoration success remains difficult due to few comparisons to reference sites or to clearly defined targets. These findings can inform future monitoring, management, and development strategies and highlight the need for preventative actions in a watershed context.

So let’s focus more on function and worry less about structure in our urban ecosystems. Let’s not settle for making them less bad. Let’s make them good!