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How to cool our cities and farms – and Earth

kid jumping in puddle raining

Michael Mobbs offers a novel solution to climate change – keeping water where it falls.

The American author Rebecca Solnit writes that hope is not the belief that everything will be fine, but at its most interesting consists of “broad perspectives with specific possibilities, ones that invite or demand that we act”.  

This is about hope. And solutions.

Think of water beads you see on a cold glass of beer or wine. Or of drips on a hot day from air conditioning pipes.

That visible water comes from invisible water vapour outside the glass or air con. The colder objects change the vapour into a liquid.

Water vapour is everywhere. And, though rarely discussed, it’s a major influence on Earth’s temperature and climate, more so than carbon dioxide pollution.

In her book, Water in plain sight, Judith D Schwartz reports there’s five times more water in the form of vapour in Earth’s air than in the form of liquid in its rivers. 

Referring to research, she adds, “a thriving forest evaporates more water than does the ocean” and it pulls moisture inland away from the ocean.

Earth’s natural water cycle is a huge air and soil-cooling machine.

Science shows that water vapour in its natural cycle is not a pollutant like the carbon being pumped into the air by we humans.  But when water as liquid in air, soil, rivers and vegetation is lost, that breaks Earth’s natural water cycle and the result is droughts, floods, and more heat. 

So, this is also about the pieties of yesterday which are burying us today – that carbon pollution is the main problem.

By saying that our misuse of water is a key cause of our collapsing climate I don’t mean to erode progress toward stopping carbon pollution. Instead, may I invite you to explore all the science of what’s breaking, and how to restore, Earth’s climate?  

I invited you to remember how water vapour is changed to liquid because I’m inviting you to “see” water in ways you may not have considered.

I’ve been working in the water field for over 30 years, and here’s a new idea to restore our climate that’s backed by science, ancient wisdom and first-hand experience. 

After being the consultant to the NSW Parliamentary Inquiry into Sydney Water and writing its April 1994 report to Parliament about new ways to use water, I rued the subsequent inaction by government and industry. 

So, in 1996, I disconnected my inner city house from mains water and sewerage system, and for the last 23 years no water or sewage has left there; it is all used for drinking and recycling. 

Through those years the four-person family enjoyed energy and water bills less than $300 a year, using free sunlight and rain, and each year over 150,000 people view a model of it in the Powerhouse Museum.

In 2008, NASA, the US agency studying Earth’s atmosphere, said, “We now think the water vapour feedback is extraordinarily strong, capable of doubling the warming due to carbon dioxide alone”.

Today NASA says water vapour is Earth’s most abundant greenhouse gas and may be the biggest cause of the planet’s broken climate.

The best solutions are being found by keeping water vapour and liquid water where they are, or returning them to where they used to be. 

In 2014, a report from the cathedral of climate science, the Intergovernmental Panel on Climate Change (IPCC) affirmed that water is one of many causes of Earth’s rising temperatures: “. . . by itself carbon dioxide is not the only and may not be the most significant cause of rising temperatures. The combination of several causes of rising temperatures multiplies the rate of heating of Earth”. 

The report goes on: 

“Land use change affects the local as well as the global climate. Different forms of land cover and land use can cause warming or cooling and changes in rainfall, depending on where they occur in the world, what the preceding land cover was, and how the land is now managed. Vegetation cover, species composition, and land management practices (such as harvesting, burning, fertilizing, grazing, or cultivation) influence the emission or absorption of greenhouse gases. The brightness of the land cover affects the fraction of solar radiation that is reflected back into the sky, instead of being absorbed, thus warming the air immediately above the surface. Vegetation and land use patterns also influence water use and evapotranspiration, which alter local climate conditions. Effective land use strategies can also help to mitigate climate change.”

The Australian farmer Peter Andrews has argued for years that Australia’s cities and farms have a “water infiltration problem” [meaning that water is not being kept where it falls], not a drought or flooding problem. Andrews, and farmers like him, demonstrate that by keeping water where it falls, they survive and continue to produce during droughts.

Trees and vegetation “control” the formation of rain, where, and how much of it falls. Together, these connected water processes control 90 per cent of Earth’s heat processes. 

Australia’s near-death Murray and Darling Rivers have dried up because nearby businesses destroy forests, trees, and vegetation and take too much water from the rivers. They don’t leave water where it falls or runs, so the water vapour disappears and now the natural water cycle is broken.

The three climate influencers – ground water, vegetation and water vapour – have a “magnetic” relationship, but only for so long as they’re near to each other. 

Remove soil or vegetation and water vapour drifts away, no longer held by its now absent partners below. 

The natural, ever-renewing generosity of the water cycle is broken, and with it the local or regional or larger climate.  Floods, drought, and soil degradation then dominate the farmland and city.

The negative impact of policies and science that focus on carbon dioxide pollution instead of restoring the natural water cycle are described by Mikal Kravcik, a scientist who has dramatically restored landscapes in Poland by keeping water where it falls:

“It is astounding, then, that while scientific publications and conferences emphasise the impacts of global warming on the circulation of water in nature, almost all of them are totally silent on the influence the water cycle has on climatic changes. The fascination with CO2 is so great, though, that it even dominates the relatively small number of scientific articles which are concerned with the relationship between vegetation and the climate . . . [scientists] don’t, however, have another formula for rescuing the planet, aside from the already mentioned prospect of lowering the levels of CO2 in the atmosphere (by lowering its production in industry, not its absorption by vegetation).”

An article in the International Journal of Water says, “It is critical that landscape management protects the hydrological cycle with its capacity for dissipation of incoming solar energy.” And continues: “Land drainage for agriculture or urbanisation usually means a loss of vegetation, resulting in a shift from the self-regulating dissipative structures described earlier, to negative consequences such as temperature swings leading to turbulent motion in warm dry air.”

But how can more of us put the science into practice? 

Projects that have been built to cool and restore local climates of farms, streets, suburbs and regions.

There’s the Indian example of villagers restoring their dead lakes using simple solutions: education, consultation with farmers, plant trees, clean waste water going into the lake, and farm fish which eat waste in the water.

And the US urban example in Elmer Avenue, Los Angeles.

Before

After

This Los Angeles project keeps stormwater, improves water quality, saves homeowners costs by reducing use of imported water, increases carbon in soil and plant tissue, creates more pleasant streetscapes, and educates the community. 

The US city of Tucson offers a rainwater harvesting incentives rebate program for single-family residential and small commercial customers.

Since 2008, Tucson has required plumbing in new homes to allow homeowners to set up greywater systems to reuse water from bathroom sinks, showers and tubs, as well as washing machines, to water plants and lawns. A third of household wastewater can be reused as greywater. The city also offers a $1000 rebate to homeowners installing permanent greywater systems.

“Sponge” cities in China and potentially in the US’s Los Angeles keep rainwater where it falls by cleaning storm water, and retaining it in vegetated gardens.

Since 2008, in the streets of inner Sydney, Australia, where I used to live, each year, for a one-off cost of $300, about 40 terrace houses and commercial buildings have been keeping over 4 million litres of rain where it falls to provide underground irrigation to trees and plants in our road gardens. We dug and laid the pipes ourselves.

Kravcik says, “Water is an asset which the individual citizen can use to improve their own life in a variety of ways. They can also, however, without any profit and for a fee, flush it into rivers and into the sea and thus slowly contribute to the desertification of their own environment and microclimate and, in time, to macroclimatic changes. The new water paradigm makes this choice a conscious one.”

Four old and new ways of viewing and using water that explain the choices available to us:

Old: Water on land does not influence global warming, which is caused by the growth of greenhouse gases produced by human activity.

New: An important factor in global warming is the change in the water cycle caused by the drying and subsequent warming of continents through human activity.

Old: The subject of research is the impact of global warming on the water cycle.

New: The subject of research is the impact of changes in the water cycle on global warming.

Old: The reason for extreme weather effects is global warming.

New: The reason for extreme weather effects are changes in the water cycle.

Old: Rising ocean levels are a result of melting icebergs.

New: Rising ocean levels are a result of melting glaciers on land, but also of a decrease in soil moistures, levels of groundwater and the state of waters on landmasses.   

When water is kept where it falls, the natural ‘air con’ effect of water in soil and in the air as vapour kicks in, and there’s less evaporation, cooler soils and air, less flooding. 

Let’s use water that’s visible and invisible, support it, and take action where we live. Let the drops stay where they fall.

In 1996 Michael Mobbs created Sydney’s Sustainable House, and is a sustainability coach specialising in off-grid projects –  practical information: Sustainable House and Sustainable Food.

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Comments

2 Responses to “How to cool our cities and farms – and Earth”

  • Thank you, Michael. Great to have your feedback.

    I do hope others such as yourself and Coombes and others also write and research and report about the power of a healthy water cycle to cool us all.

    Onwards, Michael

  • Michael Smit says:

    Hi Michael, a great discussion on an important new set of ideas. Good to see you put the Kravcik article to good use. It is always a balance to target an article to a specific point vs general principles. The water cycle may well be the most important determinant of global warming and you make a good argument. Coombes would say we need to look at the whole system and the water cycle is one of the most important components. Keeping water in place will restore natural systems. Bring it on.

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