The future of nature: The U.S. Army Corps of Engineers Turns to Nature

Here is a load of evidence from The Dirt that new designed ecologies are possible on a large scale and that they involve code sign past the usual silo-like boundaries of academia and professional affiliation. The US Army Corps of Engineers who are often reviled for their failings e.g. in New Orleans , are here showing us that it is cheaper and more efficient to design with natural systems and flows than against them.

Engineering with Nature: An Atlas / U.S. Army Corps of Engineers

“We rely on natural processes and landscapes to sustain human life and well-being. Our energy, water, infrastructure, and agricultural systems use these processes and landscapes to satisfy our most basic human needs. One motivation, therefore, for protecting the environment is to sustain the ecosystem goods and services upon which we depend. As we emerge from the sixth decade of modern environmentalism, there is a growing international awareness of opportunities to efficiently and effectively integrate natural and engineered systems to create even more value.”

One might understandably think this was written by a landscape architect, or excerpted from somewhere on the ASLA website. In fact, it comes from the forward of Engineering with Nature: An Atlas, a new book by the U.S. Army Corps of Engineers (USACE) Engineering with Nature (EWN) team, led by environmental scientist Dr. Todd Bridges. 

Over the last eight years, Bridges has quietly built the EWN initiative out of the Army Corps’ Vicksburg, Mississippi headquarters, working with a team of engineers, environmental scientists, and ecologists to develop pilot projects that prove the viability of engineering large-scale infrastructure in partnership with natural systems. 

Now, after successfully completing dozens of projects across the U.S., Bridges is pushing to take EWN to new heights. The initiative’s 2018-2023 strategic planenvisions an expanded portfolio of engineering strategies and project types, deeper interdisciplinary and community engagement, and heightened public awareness of EWN goals, activities, and success stories.

To that end, Engineering With Nature: An Atlas documents more than 50 engineering projects completed in recent decades that exemplify the EWN approach. The projects are grouped according to typology, including chapters on beaches, wetlands, islands, reefs, and rivers. Reflecting the collaborative approach of the EWN initiative, only half of the case studies profiled were carried out by the Army Corps. The remainder were executed by partner NGOs in the US and government agencies in England, The Netherlands, and New Zealand, countries which have made substantial investments of their own in innovative coastal and water-based

engineering.

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An Atlas also includes projects that retrofit conventional infrastructure to provide ecological benefits, such as creating nesting habitat for terns on top of breakwaters in Lake Erie, or efforts in the Netherlands to redesign coastal reinforcements to serve as habitat for marine plants and animals. Reminiscent of SCAPE’s Living Breakwaters project off the southern coast of Staten Island, these projects demonstrate an increasing interest in designing infrastructure that provides multiple benefits.

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Decoy terns at the Ashtabula Harbor Breakwater Tern Nesting Habitat / U.S. Army Corps of Engineers

Despite its title, At Atlas does not contain any maps or diagrams to orient the reader–an unfortunate omission that makes it difficult to grasp the scale of the presented projects. Instead, the projects are depicted using solely perspective and aerial photos.

While these photos are informative, the book would have greatly benefited from the development of a graphic language to more clearly and visually communicate the impacts of the presented projects and the issues they seek to address.

Despite these omissions, the breadth and scope of projects presented in Engineering with Nature: An Atlas makes a considerable impression, presenting a range of strategies for designing infrastructure with ecological, social, and cultural benefits at multiple scales.

Perhaps most significantly, An Atlas suggests there is great potential for meaningful interdisciplinary collaboration between the Corps and landscape architects. As landscape architects increasingly seek to broaden the field’s scope to include the planning and design of large-scale systems and ecologies, this collaboration may prove vital. Engineering with Nature: An Atlas begins to paint a picture of what such a collaborative practice may look like.

Learn more about the Engineering with Nature initiative and download Engineering With Nature: An Atlas.

A New Language For Carbon – CO2 is not the Enemy !


While searching for some information on the Cradle To Cradle certification I came across this is article by William McDonough in Nature and reviewed in Scientific American and summarised on his website

William McDonough in the ICEhouse at the 2016 World Economic Forum. Credit: Marta Chierego

This view an idea is relevant to the articles I have been posting on the site the last few weeks and to the idea of requiring all design to become CARBON POSITIVE as I state in feature post On Advocacy

Climate change is the result of breakdowns in the carbon cycle caused by us: it is a design failure. Anthropogenic greenhouse gases in the atmosphere make airborne carbon a material in the wrong place, at the wrong dose and wrong duration. It is we who have made carbon a toxin—like lead in our drinking water. In the right place, carbon is a resource and tool.

The world’s current carbon strategy aims to promote a goal of zero. Predominant language currently includes words such as “low carbon,” “zero carbon,” “negative carbon,” and even a “war on carbon.”

The design world needs values-based language that reflects a safe, healthy and just world. In this new paradigm, by building urban food systems and cultivating closed-loop flows of carbon nutrients, carbon can be recognized as an asset rather than a toxin, and the life-giving carbon cycle can become a model for human designs.

The new language signals positive intentions, leading us to do more good rather than simply less bad. It identifies three categories of carbon:

  • Living carbon: organic, flowing in biological cycles, providing fresh food, healthy forests and fertile soil; something we want to cultivate and grow
  • Durable carbon: locked in stable solids such as coal and limestone or recyclable polymers that are used and reused; ranges from reusable fibers like paper and cloth, to building and infrastructure elements that can last for generations and then be reused
  • Fugitive carbon: has ended up somewhere unwanted and can be toxic; includes carbon dioxide released into the atmosphere by burning fossil fuels, ‘waste to energy’ plants, methane leaks, deforestation, much industrial agriculture and urban development

Working carbon is a subset of all three categories and defined as a material being put to human use. For example, working living carbon is cultivated in agricultural systems. Working durable carbon is recycled, reused and reprocessed in circular technical systems; and working fugitive carbon includes fossil fuels used for power.

The new language also identifies three strategies for carbon management and climate change:

  • Carbon positive: actions converting atmospheric carbon to forms that enhance soil nutrition or to durable forms such as polymers and solid aggregates; also recycling of carbon into nutrients from organic materials, food waste, compostable polymers and sewers
  • Carbon neutral: actions that transform or maintain carbon in durable Earth-bound forms and cycles across generations; or renewable energy such as solar, wind and hydropower that do not release carbon
  • Carbon negative: actions that pollute the land, water and atmosphere with various forms of carbon, for example, CO2 and methane into the atmosphere or plastics in the ocean

Offering an inspiring model for climate action begins with changing the way we talk about carbon. Our goal is for all to embrace this new language and work toward a Carbon Positive design framework; and in doing so we may together support a delightfully diverse, safe, healthy and just world—with clean air, soil, water and energy—that is economical, equitable, ecological, and elegantly enjoyed.

Further down the IPCC CO2 hole? Or what else can we do now?

Jason King of landscape+urbanism has posted another insightful and topical examination of the implication of the latest IPCC report on global warming and particularly what is means as a landscape architect to be able to do something ..walk the talk or just understand it at least – the extract I have chosen her is relevant to my previous post of becoming CO2+ – bu toy can read the fullest on Jason’s blog here

The background is:

The connection to the science is vital to and expanded knowledge of climate change, as I mentioned in the post on the Foundations of Climate Change Inquiry. One of those foundations mentioned is the work of the Intergovernmental Panel on Climate Change, which is the body of the United Nations focusing on the global science and impacts related to climate change. Their October 2018 IPCC Special Report focuses on “the impacts of global warming of 1.5°C above pre-industrial levels and related global green house gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty.”

Likely some of us like to skip all the doom and science stuff and get to what we can do – don’t forget to read Jasons intro though….

The wide array of options for mitigation are collectively referred to as “system transformations”, as I mentioned, interesting as they include a number of landscape-specific ideas. And, based on the dire predictions of our available remaining carbon budget, reductions alone will not suffice to get us to levels that can keep warming at 1.5°C or even 2°C, especially without overshoot. Per section C.2 we require:

“…rapid and far-reaching transitions in energy, land, urban and infrastructure (including transport and buildings), and industrial systems. These system transitions are unprecedented in terms of scale, but not necessarily in terms of speed, and imply deep emissions reductions in all sectors, a wide portfolio of mitigation options and a significant upscaling of investments in those options.”

As I mentioned, efficiency is one aspect, and a combination of new and existing technologies are needed, including “electrification, hydrogen, sustainable bio-based feedstocks, product substitution, and carbon capture, utilization and storage (CCUS)”, to name but a few. I think of the book Drawdown as a good snapshot of many of these strategies and their potential. However, as mentioned, while these are technically proven at a number of scales, large-scale deployment of these is constrained, and often has trade-offs with other strategies.

We also need changes in systems, for instance section C.2.4 mentions urban and infrastructure system transitions, which imply “changes in land and urban planning practices, as well as deeper emissions reductions in transport and buildings…” to get us to these targets. Many of these are not new, but do come with some baggage: “Economic, institutional and socio-cultural barriers may inhibit these urban and infrastructure system transitions, depending on national, regional and local circumstances, capabilities and the availability of capital.”

The final section does present some interesting options, specific to CO2removal, which are collectively referred to as CDR for “carbon dioxide removal” which range in potential. These include:

bioenergy with carbon capture and storage (BECCS) 
  • afforestation and reforestation
  • land restoration and soil carbon sequestration
  • bioenergy with carbon capture and storage (BECCS) 
  • direct air carbon capture and storage (DACCS)
  • enhanced weathering and ocean alkanlinization

Two mentioned previously have some huge potential. For instance BECCS can capture up to 5 gigatons of CO2 per year, and afforestation an additional 3.6 gigatons of CO2 per year. As we find out more about the potential we can employ these strategies at larger scales, however there are trade-offs, such as the competition with other land use (for instance agriculture for food production) and the need to protect valuable ecosystem resources. One strategies mentioned is to use multiple, small installations, versus massive projects, to spread out impacts. 

Related specifically to landscape systems, the connection to ecosystem services is highlighted with the multi-functional benefits, as mentioned in section C.3.5. The use of Agriculture, Forestry and Other Land Use (AFOLU) measures for CDR, have a number of co-benefits, such as restoration of natural ecosystems providing additional soil carbon sequestration, increased biodiversity, soil quality, and food security, if managed sustainably.

Climate Positive Design – Becoming CO2+

I am on admission to understand and act on becoming “carbon positive” – I believe it is the way landscape architects can become truly relevant and effective.

A series of recent posts by Landscape+Urbanism on understanding climate change for landscape architects has been catalytic for m intoning about the role of landscape architecture, cities and our lives here on this planet. December post from the Dirt by Andrew Wright reporting on  ASLA 2018 Annual Meeting in Philadelphia and the climate positive design talk by  Pamela Conrad, ASLA, a senior associate at CMG Landscape Architecture   

“The next few years are probably the most important in our history,” said Conrad “We believe our profession can be part of the solution, and that it’s time to work together.”

Pamela Conrad has developed a calculator that predicts the emissions and carbon sequestration potential

“A few years back, I assumed I could go online and download a tool that would tell me exactly what I wanted to know. But frankly, those tools really only exist for architects right now. Because we have the ability to sequester carbon, perhaps we need our own tools to measure these impacts.”

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Landscape Carbon Calculator / Pamela Conrad, CMG Landscape Architecture

Conrad’s tool, which is still in beta testing and has not yet been publicly released, measures sources of embodied emissions in landscape materials against the sequestration potential of vegetation on a site to calculate both the carbon footprint of a project and the amount of time it will take for sequestration to completely offset emissions. Past that point, the project will  sequester additional atmospheric carbon dioxide, a condition Conrad calls being “climate positive.”

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Climate Positive Design / Pamela Conrad, CMG Landscape Architecture

Using the calculator, Conrad has been able to estimate the carbon footprints of her recently completed projects and, by tweaking the input parameters, model strategies that could have reduced their climate impacts.

“We can plant more trees and woody shrubs; we can minimize paving, especially concrete; we can minimize lawn areas; we can use local or natural recycled materials.” With these strategies, Conrad estimates that she could have cut the time it will take for her projects to become carbon neutral in half.

“The design of those projects didn’t change at all, or the quality for that matter. But what a difference it could have made if we just had the resources to inform our design decisions.”

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Carbon Positive Design / CMG Landscape Architecture

Conrad argued that, through climate sensitive design, landscape architects could be responsible for the sequestration of as much as 0.24 gigatons of carbon over the next thirty years, enough to place landscape architecture in the list of 80 solutions to climate change studied in Paul Hawken’s Drawdown project.

And “if we were to include other work we do, like incorporating green roofs into projects or making cities more walkable and bikeable, that would put landscape architecture within the top 40 solutions.”

Conrad plans to release the calculator to the public next year and hopes that it will be used to set measurable goals for designing climate-friendly projects and create opportunities for accountability.

“How are we going to keep tabs on ourselves to make sure that we’re actually doing these things?” she asked her fellow panelists. “What would it take for us to have a 2030 challenge specific to landscape architecture?”

The Foundations of Climate Change Inquiry

Jason King of Landscape+ Urbanism has written a great review and references for understanding the climate change fundamentals and I will be diving into this myself, although written for North American audience, he does reference international resources as well, for an African audience, this local book by Anton Cartwright and team from UCT’s African Centre for Cities is worth looking at Climate Change at the City Scale: Impacts, Mitigation and Adaptation in Cape Town   

In an attempt to be intentional and informed in tying landscape architecture to climate change and asking some of the fundamental questions I posed in my introductory post, I starting to develop a plan and amass a wide range of resources. Even now, I’ve barely scratched the surface, although this initial study has been illuminating, perhaps just in posing more questions. 

First, I wanted to focus on climate change mechanisms and impacts, of which there is not shortage of resources, covered in a combination of technical reports, books and articles. Second, I wanted to tap into many of the strategies from design and planning world, of which there is a steadily growing collection of articles and books, to address this in the context of solutions based in landscape architecture, architecture, and urban planning. Lastly, is the rich resource of academic journals and papers that connect the issues and approaches with a layer of evidence to further inform potential solutions. In this initial post I will focus on the first, and relate some of the initial experiences.

Climate Change Reports

One impetus for my recent obsession was the release (to much fanfare) over the Thanksgiving weekend of Volume II of the Fourth National Climate Assessment (NCA4). This report gives a detailed account of the “Impacts, Risks, and Adaptation in the United States.” Authored by an army of experts, and published by the U.S. Global Change Research Program this is the de facto standard for US Climate Science and has helped transform and amplify discussions.

Climate impact lingo

Because the IPCC’s work is so central to global scientific understand, it is helpful to get acquainted with the particular communications style of the IPCC… [it] forms a common language across fields and thus encourages interdisciplinary understanding.”Hamin-Infield, Abunnaser, & Ryan (eds), 2019 p.10

Read more…

Lets get Dirty

We are the microbial systems and live in a microbial world,  our survival as individuals, communities and as a species depend on it ! In the movie “War of The Worlds”, Steven Spielberg attributed the success of humans in surviving the aliens invasion, to our immune systems evolutionary adaptation  to withstand our microbial environment. Heres a look at how this could impact our design thinking from The Dirt

Designing Cities for Healthier Microbiomes

Artistic rendering of the human microbiome / The Why Files

Humans are essentially super-organisms or holobionts made up of both human cells and those of micro-organisms, such as viruses, bacteria, archea, protists, and fungi. Researchers now know the human body hosts a comprehensive ecosystem, largely established by age three, in which non-human cells vastly outnumber human cells. The latest study from the American Academy of Microbiology estimates each human ecosystem contains around 100 trillion cells of micro-organisms and just 37 trillion human cells.

But while rainforest or prairie ecosystems are now well-understood, the human ecosystem is less so. As researchers make new discoveries, there is a growing group of scientists who argue our microbiomes are deeply connected with our physical and mental health. The increased number of prebiotics and probiotics supplements on the shelf in drug stores and supermarkets, and availability of fresh pickles and kimchi in local farmers markets, are perhaps testaments to this increasingly-widespread belief.

The question at the Environmental Design Research Association (EDRA) conference in Oklahoma City was: Can we design cities to better support our microbiomes and in turn our overall health?

Through urban farming and gardening — or just plain playing in the dirt — humans can also increase their exposure to healthy microbes found in soils. A group of scientists and advocates argue that greater exposure could help fight depression and anxiety and reduce rates of asthma and allergies in both kids and adults.

The incredible increase of allergies among Western populations may be caused by our “sterile, germ-free environments” that cause our immune systems to over-react to everything from nuts to mold and pollen. Dr. Brett Finlay and Marie-Claire Arrieta even wrote a book exploring this: Let Them Eat Dirt: Saving Your Child from an Over-sanitized World.

Wener said we have created cities that reflect our fear of bacteria; instead we must create microbial-inclusive cities that improve our health. “Most microbes in our bodies have co-evolved with us. They are important to our vital functions. The future of urban planning and design should support healthy microbes.”

As part of this vision, landscape architects could design parks and plazas to be filled with accessible garden plots and soil-based play areas that let both adults and kids get dirty. We could design for holobionts instead of just people, boosting the health of the collective urban microbiome in the process.

Wener’s colleage at NYU — Elizabeth Henaff — is leading much of this research. Learn about her artful experiments. Read this article from Michael Pollan in The New York Times outlining the connections between our microbiome and health, and this Q&A from The Guardian.

Read the full article

THE SHAPE OF WATER

From Jason King’s Landscape+Urbanism site

 

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“Rendering of Houston wetland channel showing ecological wetland, conservation areas, and recreation trails” p. 90-91

An amazing resource posted on ASLA’s The Dirt (here) focuses on Design Guidelines for Urban Wetlands, specifically what shapes are optimal for performance. Using simulations and physical testing to investigate hydraulic performance the team from the Norman B. Leventhal Center for Advanced Urbanism (LCAU) at MIT. Led by Heidi Nepf, Alan Berger and Celina Balderas Guzman along with a team including Tyler Swingle, Waishan Qiu, Manoel Xavier, Samantha Cohen, and Jonah Susskind, the project aims to have a practice application in design guidance informed by research. From their site:js_plan_typical-01

“Although constructed wetlands and detention basins have been built for stormwater management for a long time, their design has been largely driven by hydrologic performance. Bringing together fluid dynamics, landscape architecture, and urban planning, this research project explored how these natural treatment systems can be designed as multi-functional urban infrastructure to manage flooding, improve water quality, enhance biodiversity, and create amenities in cities.”
Starting in the beginning by outlining ‘The Stormwater Imperative’, the above goal is explained in more depth, and issues with how we’ve tackled these problems are also discussed, such as civil-focused problem solving or lack of scalability, but also explore the potential for how, through intentional design, these systems “can create novel urban ecosystems that offer recreation, aesthetic, and ecological benefits.” (1)

single_island

The evolution that has resulted in destruction of wetlands through urbanization, coupled with deficient infrastructure leads to issues like flooding, water pollution due to the loss of the natural holding and filtering capacity of these systems and the increased flows. However, as pointed out by the authors, this can be an opportunity, as constructed wetlands “can partially restore some lost ecosystem services, especially in locations where wetlands do not currently exist.” (5)

The modeled flow patterns are also interesting, showing the differentiation from fast, regular, slow flows, along with any Eddy’s that were shown in dye testing using the flumes.

Read More

Check it out and see what you think.  The report is available as a online version via ISSUU or via PDF download from the LCAU site, where there are also some additional resources.  All images in this post are from these reports and should be credited to the LCAU team.

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Landscaping in post Day Zero Cape Town

BY  Kay Montgomery From SALI  South African Landscapers Institute

Planting with species that thrive on less than 500mm of winter rainfall a year is the new reality for landscaping in Cape Town.   

The politicians may have done away with the Day Zero concept, but the realities of the water situation in the Western Cape remains dire.

Water restrictions and the price of potable water have encouraged a new landscaping reality. The foundation of this reality is based on landscaping with plants that thrive with less than 500mm of winter rainfall. And in our current era of climate change, coping with dramatically wet years – followed by dramatically dry years.

Highs and lows

With an average rainfall of 464mm per annum, South Africa remains a water scarce country. In years gone by, Cape Town’s average rainfall was 820mm per annum. In 2013 and 2014, Cape Town’s annual rainfall exceeded this average with two dramatically wet years.

The winds of change arrived in 2015.  Over the past three years, the rainfall received in Cape Town has swung way below the average:  549mm in 2015, 634mm in 2016 and 499mm in 2017 – the driest year since observations began in 1921.

Resilient landscaping

Against this backdrop, landscapers are practising the art of resilient landscaping. “We need green spaces in our cities”, says Norah de Wet, Chairperson of the South African Landscapers’ Institute (SALI). “Professional landscapers are at the forefront of securing the intrinsic value of properties across the Western Cape by refitting, rehabilitating, restoring and installing resilient landscapes”.

Planting for resilience

“Choosing plants that can thrive in a winter rainfall area with less that 500mm a year of rainfall is key to the concept of resilient landscaping in the Western Cape”, says Deon van Eeden from Vula Environmental Services.  “Only with a sound knowledge of fynbos flora, can one succeed in designing water wise, ecologically sound, resilient landscapes for the winter rainfall area”, he adds.

 

What happened here ? Cape Town’s failed water supply?

Awaiting Day Zero: Cape Town Faces an Uncertain Water Future

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After Cape Town restricted water use in February to 13 gallons per day per person, city residents now wait in increasingly long lines to collect water from the city’s natural springs.  AP PHOTO/BRAM JANSSEN 

South Africa’s second-largest city has pushed back the day when its taps are expected to run dry. But with its population growing and the climate warming, Cape Town, like many cities in semi-arid regions, must take decisive measures to meet its future water needs.

Backed by the iconic Table Mountain, Cape Town, South Africa’s second-largest metropolis, seduces increasing numbers of international travelers. Its charismatic neighborhoods, bright beaches, and breathtaking natural landscapes garner shelves-full of tourism awards and terabytes of glowing Instagram posts.

Recently, Cape Town also has become infamous as the home of “Day Zero,” the day when most of the city’s taps are predicted to run dry. With its major, rain-fed supply dams dangerously low after three years of drought, most of the city’s 4 million-plus residents — some rich, many desperately poor — have been facing the prospect of lining up at emergency water distribution points to collect a daily ration of just 6.6 gallons per person sometime before June or July. That’s when winter rains normally begin filling the reservoirs of this Southern Hemisphere city.

Now, largely thanks to radical conservation efforts — in January, the average Cape Town resident’s daily water quota was just one-third the amount used by the typical Californian at the height of that state’s 2016 drought — the city has reduced water consumption by 57 percent. Day Zero has been pushed back to July 9. And if the citizens of Cape Town (myself among them) continue to save as we have been, we should make it to the winter rainy season without having to line up for water.

So, disaster averted? Nothing to see here anymore? Far from it. The city’s efforts on the supply side of the water equation have been far less successful than its work on consumption. Even if the drought comes to an end in 2018 — and few experts are willing to predict that — the effects of this water crisis will be felt for years, possibly decades.

How did Cape Town, one of the best-managed and wealthiest cities in Africa, find itself on the brink of running dry?

Cape Town’s predicament provides a global warning about the difficulty of ensuring water resilience in a warming world, even if, as with Cape Town, climate change is firmly on the agenda of city managers. Most climate models predict that the Cape Town region will become not only warmer, but drier, which bodes ill for a metropolitan area whose population has roughly doubled to 4 million in the past three decades and continues to grow at 1 to 2 percent annually.

And Cape Town’s rushed efforts to boost water supply by tapping into aquifers, including some in national parks and provincial nature reserves, are damaging valuable ecosystems and putting rare species at risk of extinction. The agricultural sector, including the Cape region’s world-renowned wine industry, has been forced to sharply cut back on irrigation, which is reducing production and leaving tens of thousands of people out of work.

So how did Cape Town, one of the best-managed and wealthiest cities in Africa, find itself on the brink of running dry? The city has, after all, won awards for its work on climate change. South Africa has some of the world’s most detailed, progressive water laws and deep expertise in water science and management, climate science, and meteorology. The city has mapped projected sea level rise and convened countless climate change adaptation planning sessions. Last year, Cape Town’s mayor said, “We cannot plan anything without factoring in the impact of climate change.”

People wait to collect water from a natural spring in the Cape Town suburb of St. James in January 2018.

People wait to collect water from a natural spring in the Cape Town suburb of St. James in January 2018. RODGER BOSCH/AFP/GETTY IMAGES

A simple (and perhaps simplistic) answer to the cause of the current crisis is that rainfall was well below average for three years in a row, that no one could have or did predict that, and thus serious action to reduce water consumption — which should have begun in 2016 — came too late.  The crisis has exposed significant weaknesses in scientists’ ability to forecast weather on a seasonal scale, which is when it matters to city managers and farmers, and predict rainfall on an annual or decadal scale, which is when it matters to developers of large-scale infrastructure, such as raising dam heights and building desalination plants.

The southwestern part of South Africa has a Mediterranean climate much like the central coast of California, with hot, dry summers and cool, rainy winters (June through August.) The winter rains fill the six large dams around the city that form the core of the Western Cape Water Supply System (WCWSS), which services the vast majority of the city’s residential and industrial water users, as well as farming areas and smaller towns nearby.

The winter rains are generally very reliable. Using historical rainfall data, Piotr Wolski of the Climate Systems Analysis Group at the University of Cape Town has determined that a multi-year drought as severe as the current one would only be expected once every few hundred years, perhaps less than once in a millennium. The ongoing drought in the catchments of the WCWSS dams, he writes, “is indeed very, very rare, and thus very, very severe.” The historical rainfall record indicates that, having had two poor rainfall years in a row (2015 and 2016), the chances of a third bad year – especially one as bad as 2017 – were extremely remote.

In addition to historical data pointing to the extremely low likelihood of 2017’s winter being dry, the South African Weather Service modeled a three-month seasonal forecast for the winter of 2017 that predicted higher than average rainfall.Notwithstanding that seasonal rainfall forecasts for the Cape region are notoriously unreliable, it appears that officials were left feeling less urgency to impose hugely unpopular water restrictions or push forward with expensive water infrastructure projects early in the year.

Experts have long warned that Cape Town would find itself in a water crisis caused by converging drought, population growth, and the failure to secure new water resources. But because of uncertainties in water consumption rates and in weather and climate prediction, it’s been hard to fix a date.

The city’s water consumption has fallen from 317 million gallons per day in early 2015 to about 137 million gallons per day.

 Read More

Continue reading

What is one thing every ecologist should know about urban ecology?

Introduction
An ecology for the Anthropocene

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The High Line in New York City. Photo: David Maddox

Urban ecology has expanded in the last couple decades as a major, global, interdisciplinary field that advances biodiversity, sustainability, and fundamental ecological research in the context of cities and urbanization. With all this accumulated learning, has urban ecology made its mark in the field of ecology more generally?
In some of the most important peer-reviewed ecology journals, and on social media, it seems even the most basic of urban ecology concepts have yet to be appreciated or incorporated in the broader ecology discipline. For example, it’s been 25 years since Humans as Components of Ecosystems was published, and yet many ecologists still don’t see humans as part of how we define and study nature—despite the fact that every ecosystem on earth is affected by, and has effects on, people.

The High Line in New York City. Photo: David Maddox
In November 2017, Nature Ecology and Evolution published a major review of the field of ecology, titled “100 articles every ecologist should read” (behind a paywall, unfortunately). It must be noted that the list was a product of a extensive survey of ecologists. Nevertheless, many ecologists around the world took exception to the lack of gender and racial diversity, and its general lack of inclusivity (see here, here, and here). Notably lacking from these academic discussions has been a recognition of core contributions from urban ecology to how we understand, manage, and plan ecosystems on our urban planet.

It begs the question: what would a reading list be for the discipline of ecology in the Anthropecene? But we are getting ahead of ourselves.

No one disputes that the 100 papers listed by Nature Ecology and Evolution are important in the history of ecology. Indeed, everyone should read these papers. But is this the right list of 100 papers to understand ecology today? There are other papers that should make a reading list for a complete understanding of modern ecology. An alternative version of a “key reading” prompt could be this: what are the 100 papers that every ecologist must read to understand ecology today, in the Anthropocene? Social ecology, biophilia, justice, poverty, gender, values, the Global South, design, climate change, policy; these are just some of the topics that are core material for understanding the broad science of ecology today, These topics are largely missing from the 100 papers list.

And also missing, of course, is urban ecology.

As it happens, urban ecology routinely includes the aforementioned list of additional topics: social ecology, biophilia, justice, policy, and so on. How does urban ecology advance the state of the art in ecology more generally? It advances our understanding of how our current world works, how it might work better, and it lays foundations to turn that learning towards pressing Anthropocene challenges, both urban and non-urban.

We asked a diverse group to help our non-urban ecological colleagues understand some of the most important contributions from urban ecology for advancing the field of ecology. We asked them this question: What is one thing every ecologist should know about urban ecology? (We asked them to suggest a reading also—a start on a reading list.)

Along the way, let’s expand the idea of “ecology”.

via What is one thing every ecologist should know about urban ecology? – The Nature of Cities