The power of water to cool the Earth is bigger than we think
Michael Mobbs | 7 November 2017
Feel the force, Luke, be the force – Star Wars I
Feel the drop of rain, be the raindrop – Me*
BATHURST BURR: “It looks like it looks at the end of summer”, the farmer said, crumbling the dry, dead tree leaves in his fingers. “Never seen trees like this die, this is their country, they’re survivors.”
It was the end of winter on this country farm, 350 kilometres inland, over the Blue Mountains from the coastal city of Sydney, Australia.
Summer was coming in 2017.
We looked at the dead trees and plants around us, wondering, silent.
For the last dozen or so years I’ve been having similar conversations with other farmers and country folk across Australia. Inland Australia, over the mountains away from where most Australians live near the sea, has the nation’s fastest increases in temperatures. It’s never been so dry in white people’s history.
When it rains, the too-dry soil rejects the water and carries it away, to flow faster into rivers where the novel sediment kills the plants and aquatic life.
In cities such as mine I can’t so easily see the changes being wrought on the countryside by higher temperatures, except in my house’s 10,000 litre rain tank which now fills less reliably. Water’s role in affecting local and Earth-wide climates, and its potential for good, is not on the radar for city-dwellers.
Wasted rainwater is a key. It may be a cause of climate change. Science shows that keeping water where it falls may be the vital key to cooling Earth.
As long ago as 2008, Eric Fetzer, an atmospheric scientist who works with the Atmospheric Infrared Sounder (AIRS) data at NASA’s Jet Propulsion Laboratory in Pasadena, California, said, “Water vapor is the big player in the atmosphere as far as climate is concerned.”
Fetzer’s research team used new data from the Atmospheric Infrared Sounder on NASA’s Aqua satellite to measure precisely the humidity through the lowest 16 kilometres of the atmosphere. That information was combined with global observations of temperature shifts, allowing researchers to build a comprehensive picture of the interplay between water vapour, carbon dioxide, and other atmosphere warming gases.
Wasting water – by not keeping most of it where it falls – appears to cause more rapid climate change than does carbon dioxide, and may be the main contributor to modern sea level rise:
“While global warming is commonly attributed to atmospheric CO2, the research shows water vapour has a concentration two orders of magnitude higher than other greenhouse gases. It is critical that landscape management protects the hydrological cycle with its capacity for dissipation of incoming solar energy.” (Solar energy dissipation and temperature control by water and plants Int. J. Water, Vol. 5, No. 4, 2010 311, Inderscience Enterprises Ltd.)
Yet, when the power of water is understood and respected, magic happens.
There seem to be two factors which can bring about dramatic changes to how a society manages water: culture, and money.
Let’s consider culture first.
It’s possible to double a country’s food growing capacity in 20 years where food and water and people are passionate about the cause. The country and city-wide example of the Netherlands shows that almost two decades ago, the Dutch made a national commitment to sustainable
agriculture under the rallying cry, “Twice as much food using half as many resources,” according to this National Geographic Magazine article, How on Earth have the Dutch done it?“:
Since 2000, van den Borne [a Netherlands farmer] and many of his fellow farmers have reduced water dependence for key crops by as much as 90 per cent, the article says. They’ve almost completely eliminated the use of chemical pesticides on plants in greenhouses, and since 2009 Dutch poultry and livestock producers have cut their use of antibiotics by as much as 60 per cent.
The Netherlands is a small, densely populated country, with more than 1300 inhabitants per square mile (2.6 sq kms) bereft of almost every natural resource long thought necessary for large-scale agriculture. Yet it’s the globe’s number two exporter of food as measured by value, second only to the United States, which has 270 times its landmass.”
In the last few years of this decade, however, the Netherlands has experienced rainfall and flooding at volumes and frequencies which previously occurred only every 200 years or so. Tunnels, building basements, roads, electrical and transport infrastructure have flooded several times across cities and country-sides. That’s manageable now and then, but not several times every year.
One eighth of the country is half a metre below sea level, half is one metre above sea level and is lived and farmed only because the sea is excluded by large barrier sea walls, the National Geographic article says.
The country risks becoming uninhabitable by 2050 and is building new barriers because it expects a one metre sea level rise by 2100.
The sense of urgency to sustain the water cycle – the knowledge of the power, purpose and vitality of water, and the social will that provoked action to use water prudently and grow food as Netherlands did – are absent in Australian culture.
In that small country, farms are close to the villages and cities; strong visual and practical connections exist between urban and country folk. By contrast, Australia exports over two thirds of its food, 40 per cent of which is grown in the remote Murray Darling Basin, located far inland from cities located on the coast, and those food growing places and their viability is dimly understood in the cities where over 87 per cent of Australians live.
Urban farms in Australian cities and towns provide a visual guide for urban people to the way food is grown, what food plants look like, how the plants need water and, if they may taste or buy it, how healthy and tasteful such food and gardening for it can be; in this context we might think of urban farms as practical and cultural “mini Netherlands”.
What about the second factor, money?
In 2016 NSW’s Independent Pricing and Regulatory Tribunal created a new pricing mechanism to reduce storm-water pollution. In an incomplete application of the polluter pays principle, IPRT reduced the amount Sydney Water charges for storm-water by 68 per cent for “low impact” properties where more than 60 per cent of rainwater is retained on site.
In a baffling decision that lacks rationality, if a property owner pollutes not at all by keeping all the rainwater on site, there is still 32 per cent of the oldcharge to pay.
Outside the world of recent arrivals to the polluter pays principle, IPRT and Sydney Water, the water policy environment is like a desert: polluter pays pricing is yet to touch the minds or budgetary processes of local government councils which in Sydney and across Australia continue to operate with no financial rewards for those who pollute less, whether it’s water, air or other pollution.
Moving on, let’s consider what science tells us about the uncaptured value to Sydney Water’s business of keeping rainwater where it falls in catchments and urban areas.
As I understand the science, there’re still a few years left to increase Sydney’s water security (before climate change makes it impossible by 2030), and to cut Sydney Water’s contribution to climate change due to evaporation in its catchments and customer areas.
Sydney Water, local government councils and property owners wishing to cool the city quickly can do so if they give priority to keeping water where it falls.
Peer-reviewed science persuades me this goal is as important to Sydney Water’s business as is its business of selling water and waste water services.
Water vapour is a greenhouse gas
Water vapour is known to be Earth’s most abundant greenhouse gas. Science confirms it can at least double the warming impact of carbon dioxide.
Evaporation rates in Sydney and inland Australia are increasing due to temperatures increasing there. Wasting water in catchments and urban areas increases the temperature and evaporation, increases the rate of local and regional climate change, disrupts weather and reduces security of water supply.
The research I’ve seen about Sydney’s security of water supply focuses on climate change, and ignores potential to increase supply by reducing evaporation in catchments and customer areas.
The science has prompted me to consider options which provide solutions to these questions:
- Will there be greater security of water supply to Sydney if most rainwater in the catchments and urban areas is kept where it falls in volumes mimicking the natural, pre-development water cycle?
- Water evaporation is a key greenhouse gas and can double the impact of carbon pollution
- How can Sydney Water reduce evaporation in its catchments?
Do these questions raise issues which go to the heart of the statutory duties of the directors of the Board of Sydney Water?
If water vapour doesn’t turn you on – I can understand that – and you’re unconvinced, and still reading, how about something we see every day, cement and concrete?
“Concrete is the second most consumed substance on Earth after water.”
Cement causes five per cent of Earth’s carbon pollution. Making a tonne of cement also puts a tonne of carbon into Earth’s atmosphere.
I mention cement because it’s everywhere in cities; just as we don’t “see” it because it’s everywhere and we may take it as “natural”, so, too do we not “see” water. I’m writing here to invite us to look again at water and bring our fresh eyes when we look at it – to refresh. Consider this:
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.
In relation to global warming, it is recognised that while humans induce CO2 emissions by land clearing and burning fossil fuels, ecosystems bind CO2 in the biomass of plants and soil. What is less often realised is the fact that the annual increase in humanly induced carbon in the atmosphere is an amount equivalent to only 0.6 per cent of the carbon contained in vegetation and 0.2 per cent of the carbon contained in soils.
Studies by Beran (1994) and IPCC (2007) put the annual increment of carbon in the atmosphere from CO2 emissions at 3.5 GT. In soil, there is c. 2000 GT of naturally occurring carbon; in vegetation 610 GT and in the atmosphere 750 GT of carbon. These various sources exchange carbon in a functional relation to each other, a dynamic that is uncoupled when local water cycles are damaged.
This lost functioning is observed on a global scale in the Millennium Environmental Assessment (2005), which notes that every year, some 60,000 square metre of badly managed land is becoming desert.
About 200,000 square m of land loses agricultural productivity as people in development projects or farmers themselves cut down plants and drain soils. The drying out and loss of ecosystem function now affects 30–40 per cent of the global landmass.”
– Solar energy dissipation and temperature control by water and plants Int. J. Water, Vol. 5, No. 4, 2010 311 Copyright 2010 Inderscience Enterprises Ltd.
Wasting water when we farm and building cities in ways which take water for granted is a major cause, not a symptom, of Earth heating up.
Let’s make keeping water where it falls a daily part of any form of new or existing development, whether it’s roads, drains, houses, buildings or parks.
We do this in my street. Anyone can.
Since 2008, at a one-off total cost of less than $300 we built 18 leaky drains outside participating houses which each year keep over 4 million litres of rainwater in our road gardens. Here’s a three minute video showing how anyone can do this in 20 minutes, easily.
* Some humility from me: we don’t yet know for sure where Earth’s water came from; whether it was part of matter which formed the planet or, perhaps, was brought by watery comets when they crashed here. We know so little about our planet. So, yes, I’m guided by the science but, as no one has saved a planet, the true story here is that my suggestions are really just a best guess.
Michael Mobbs is a Sustainability Coach, creator of Sydney’s Sustainable House, Sydney. See here for more information.