Passive Daytime Radiative Cooling.

The most effective form of renewable, low-carbon energy is energy not used at all. Passive daytime radiative cooling (PDRC) is a method proposed to ameliorate global heating, by enhancing the radiation of heat to outer space using thermally-emissive surfaces placed around the Earth. There is no energy consumed in running this technology, and hence no associated greenhouse gas emissions. Since all natural materials absorb more heat during the day than at night, PDRC surfaces are designed with a high solar reflectance (to minimize heat gain) and strong thermal (heat) radiation transfer through the atmosphere's infrared window (in the region, 8–13 µm), so that temperatures are reduced during the daytime. PDRC offers the advantage over solar radiation management that it increases the emission of radiative heat, rather than merely reflecting solar radiation back into space before it is absorbed by the environment and heat thus generated from it.

It has been estimated that if PDRC were installed over 1–2% of the Earth's surface area, a brake would be applied to relentless global heating, and temperature increases reined in to survivable levels. The cooling potentials are greater for desert and temperate regions than for tropical climates, since both humidity and cloud cover inhibit the efficiency of the devices. Cheap materials have been developed for PDRC that can be mass produced, including coatings, thin films, aerogels, and metafabrics, to reduce the need for air conditioning, attenuate the urban heat island effect, and cool human bodies in conditions of extreme temperature.

Scientists at MIT have invented a PDRC device that can cool things down by more than 13 degrees Celsius, and significantly below the ambient air temperature, in full sunlight on a cloudless day. The critical component for this device is a polyethylene foam insulating material called an aerogel. The foam is extremely lightweight (just 1/50th of the density of water), looks and feels somewhat like a marshmallow, and both blocks and reflects the visible rays of sunlight, thus preventing them from passing through it. It is also transparent to the infrared radiation wavelengths that transport heat, so they can escape and be radiated out and away.

Hot objects cool down as a result of radiative heat loss, emitting midrange infrared radiation. Since air is effectively transparent to these wavelengths, the heat energy is lost into space.

The basic concept was demonstrated a year ago, using a narrow strip of metal, as a physical barrier to shade the device from direct sunlight, and prevent it from heating up. However, its cooling power was less than one half that the new system, with its highly efficient insulating layer, without which the heat from the surrounding air raises the temperature of the device.

The use of air conditioners and electric fans already accounts for about 20% of the total electricity consumed in buildings around the world, which amounts to around 10% of current total global electricity consumption. It is expected that demand for air conditioning will increase from the current 1.6 billion to 5.6 billion AC units by 2050, becoming one of the top drivers of global electricity demand, despite negative consequences in terms of increased energy use, costs, and global warming, described as a "vicious cycle.”

This situation may nonetheless be mitigated, since PDRCs are most often applied to building envelopes, which can significantly lower the temperatures within. When a  reflective white roof was combined with a PDRC, a doubling of the energy saved for cooling could be obtained. Elsewhere, it is quoted that PDRC coatings directly covering a roof reflect a large proportion of solar radiation and achieve a lower roof temperature, which can reduce cooling loads by 18%–93%. By covering 10% of a building's roof with a multilayer PDRC surface, some 35% of air conditioning used during the hottest hours of the day can be avoided. Hence, PDRCs can act to replace, or reduce the energy demand of, air conditioning, and also help to ease the pressure on energy grids during periods of peak demand.

It has been reported that, in suburban residential areas in the United States, PDRCs can result in a 26%–46% reduction in energy use and an average lowering of temperatures by 5.1 °C.

With the addition of "cold storage to utilize the excess cooling energy of water generated during off-peak hours, the cooling effects for indoor air during the peak-cooling-load times can be significantly enhanced" and air temperatures may be reduced by 6.6–12.7 °C. 

As global temperatures increase, such PDRC cooling devices may find widespread applications, with the advantage that they use no energy, incur no greenhouse gas emissions, and hence do not add to the burden of global heating, unlike conventional refrigeration and air conditioning systems which need electricity to run them.

Integrated, hybrid systems, that combine thermal insulation, evaporative cooling and radiative cooling, can also be used to perhaps double the time that fruit and vegetables can be kept fresh, and in remote regions where refrigeration is not viable due a lack of a reliable electricity supply.

However, there are a number of challenges attendant to a wide scale commercialisation of PDRC, that must be considered: for example, the cost and availability of the materials employed to fabricate particular devices, along with their durability (lifetime) and performance under prevailing environmental conditions, which will vary appreciably according to location.

"The Force that through the Green Fuse Drives the Flower."

 "The Force that through the Green Fuse Drives the Flower", is the title of a poem by the Welsh poet, Dylan Thomas, and which can be read as a metaphor for photosynthesis, with chlorophyll as the green fuse "ignited" by sunlight firing a plant into bloom, although the following allusion that it also "...drives my green age" encompasses the whole force and process of aliveness, including that of the writer of those words. I have often marvelled at the urge of nature to bring forth life, and its capacity to do so, even in very inhospitable conditions, where it may cling on precariously, and was struck by these plants, alive, if not all fully thriving, in the fast moving waters of the weir at Caversham Lock, fed by the River Thames. 

Most probably, they are rooted in sediment, delivered by the river over time or, as the weir is now quite old, into its foundations. Anyway, here are a few examples of what is growing there, providing an organic interface ("edge", in permaculture terms) between water, steel and concrete. 

First a curly- dock (Rumex crispus):

Next to this is a buddleia (buddleja), seemingly anchored to the steel frame of the weir:

And to the other side of that dock is a grey willow (Salix cinerea), also fixed to the steel frame, but extending roots:

The capacity of nature to bring forth life is a wonder, and a demonstration that our intentions should not be focussed to "Save the Planet" - an almost arrogant view considering the immensity of a planet in comparison with the puny human scale - but that we need to respect Nature to comprehend our place as part of it, and at best save ourselves. The book, "The World Without Us", amply expresses that if we fail to accomplish this, most traces of "us" - the human civilization - will be overwhelmed and erased.

Thus, I am also reminded of the sonnet by Percy Bysshe Shelley, entitled Ozymandias (the name from ancient Greek sources for the pharaoh Ramesses II - "Ramesses the Great"): 

"I met a traveller from an antique land,

Who said—“Two vast and trunkless legs of stone

Stand in the desert. . . . Near them, on the sand,

Half sunk a shattered visage lies, whose frown,

And wrinkled lip, and sneer of cold command,

Tell that its sculptor well those passions read

Which yet survive, stamped on these lifeless things,

The hand that mocked them, and the heart that fed;

And on the pedestal, these words appear:

My name is Ozymandias, King of Kings;

Look on my Works, ye Mighty, and despair!

Nothing beside remains. Round the decay

Of that colossal Wreck, boundless and bare

The lone and level sands stretch far away.”

Similarly, I have climbed Mount Nemrut in Turkey - walking along its edge in an almost paralysingly powerful wind - to view its mountain top tomb-sanctuary flanked by huge 8–9-metre high (26–30 ft) statues of King Antiochus IV of Commagene, two lions, two eagles, and various Greek and Iranian gods, including Heracles-Artagnes-Ares, Zeus-Oromasdes, and Apollo-Mithras-Helios-Hermes. Although the King felt inclined to thus elevate himself beyond the mortal and into the divine realm, the head of his statue has fallen along with the others, as another metaphor for the flimsy transience of human accomplishments and illusory omnipotence, in the face of amaranthine natural forces that will prevail with or without us.

"Living the Change," Film Screening + post-film Q&A. 6 pm, April 17th (2023), Reading Biscuit Factory (Reading, UK).

You can either just turn up on the night and buy a ticket there, or book tickets in advance from this link:  https://www.readingbiscuitfactory.co.uk/checkout/showing/living-the-change-qa/54631

This is a film screening (+ post-film Q&A), arranged with Transition Town Reading, to be held at the independent cinema, "Reading Biscuit Factory", at 6 pm on April 17th (2023), and here is the booking link (or just turn up on the door) https://www.readingbiscuitfactory.co.uk/movie/living-the-change-qa

Overview

Living the Change is a feature-length documentary that explores solutions to the global crises we face today – solutions any one of us can be part of – through the inspiring stories of people pioneering change in their own lives and in their communities in order to live in a sustainable and regenerative way.

Directors Jordan Osmond and Antoinette Wilson have brought together stories from their travels, along with interviews with experts able to explain how we come to be where we are today. From forest gardens to composting toilets, community supported agriculture to time banking, Living the Change offers ways we can rethink our approach to how we live.

Includes post-film Q&A with:

Professor Chris Rhodes, Director of Fresh-lands Environmental Actions, and Chair of Transition Town Reading

Peter Wheat, Reading Food Growing Network, and Transition Town Reading

Trish Whitham, Permaculture practitioner and educator

"Living the Change," Film Screening + post-film Q&A. 6 pm, April 17th (2023), Reading Biscuit Factory (Reading, UK).

This is a film screening (+ post-film Q&A), arranged with Transition Town Reading, to be held at the independent cinema, "Reading Biscuit Factory," at 6 pm on April 17th (2023), and here is the booking link (or just turn up on the door) https://www.readingbiscuitfactory.co.uk/movie/living-the-change-qa

Overview

Living the Change is a feature-length documentary that explores solutions to the global crises we face today – solutions any one of us can be part of – through the inspiring stories of people pioneering change in their own lives and in their communities in order to live in a sustainable and regenerative way.

Directors Jordan Osmond and Antoinette Wilson have brought together stories from their travels, along with interviews with experts able to explain how we come to be where we are today. From forest gardens to composting toilets, community supported agriculture to time banking, Living the Change offers ways we can rethink our approach to how we live.

Includes post-film Q&A with:

Professor Chris Rhodes, Director of Fresh-lands Environmental Actions, and Chair of Transition Town Reading

Peter Wheat, Reading Food Growing Network, and Transition Town Reading

Trish Whitham, Permaculture practitioner and educator

“The Oil Machine” and the Changing Climate.

Released smartly in time for the COP27 climate change conference, the film “The Oil Machine", presents a stark picture of the imperative to cut our use of fossil fuels, in particular crude oil, but moreover of our utter dependency on the “black gold” for practically all aspects of modern civilization. While it is clear that further licenses should not be permitted for new oil exploration and production, in line with the International Energy Agency’s Net Zero by 2050 roadmap, it is likely that oil companies would need to be accordingly compensated for their losses. However, although the UK government appears set to grant another 100 licenses in the North Sea, this would not necessarily guarantee energy security for the UK, since much of the production there is in the hands of foreign agencies. 

A tricky dilemma is nonetheless presented, as European nations scramble to get hold of hydrocarbons from alternative sources, in part to avoid supporting Putin’s war machine, but also now that there is no Russian gas coming to Europe down the Nord Stream 1 pipelines, which have suffered damage from deliberate sabotage, although it is not yet clear exactly who put the explosives there for the job. While the finger of blame seems to oscillate in its direction, depending on exactly who is pointing it, efforts to maintain current levels of oil and gas through this winter and beyond, strengthen their grip, while renewable energy is pushed onto the proverbial back burner.

The film admirably emphasises the extent and complexity of the oil and gas pipeline network under the North Sea, and on land too, which is conveniently but deceptively out of sight and hence out of mind; yet it is this sprawling and fragile infrastructure whose bounty underpins the mechanics of our daily lives. We are indeed living within “the oil machine”, not only through our use of oil and gas for fuels, but our increasing reliance on oil-based products, such as plastics (think phones, computers, clothes, vehicles, packaging, toys and utensils), pharmaceuticals, and fertilizers and pesticides for agriculture. While almost no one can be unaware of the fact of plastic pollution, its close connection to the oil industry is less well known, even though making plastics consumes 6% of the global oil supply (including natural gas liquids). 

Here the film scores highly, in its expression of the interconnected nature of energy, jobs, finance, geopolitics and climate change, and that while we need to stop burning oil and gas to curb CO2 emissions, we can’t “just stop oil” overnight, or the system of civilization would collapse.

Nonetheless, we have precious little time left to substantially curb our use of fossil fuels – when I began writing on these subjects back in 2005, 2030 seemed almost comfortingly distant, but is now only 7 years away. However, this alone is not the whole story, since even if greenhouse gas emissions are rapidly and dramatically cut, the vast polar ice-bodies will continue to melt, thus raising sea levels in a relentless process, lasting over centuries. 

Further melting of the Arctic ice could provide a catastrophic feedback, if methane, with a heating potential one hundred times that of CO2, is released into the atmosphere from decomposing methane hydrate deposits, increasing global temperatures by 5 - 8 degrees, and rendering large regions of the Earth effectively uninhabitable. Following such a course, mass migrations of millions would be almost inevitable.

Since 81% of global production is currently in decline, to reduce the use of oil is not entirely our choice, as IEA Executive director, Fatih Birol, has noted, “We have to leave oil before it leaves us.” 

Thus, to replace this loss, and maintain the overall flow of “oil” into industrialised civilization is an increasingly difficult, energy intensive and expensive process. Indeed, the loss of investment capital into the oil industry may well secure its demise, if it is no longer seen as a viable commodity. Hence, for this reason too, we need to look to alternative energy sources and, more generally, ways of actuating our lives that do not depend on oil.

While “The Oil Machine” delivers a hard punch over the status quo, it also makes clear that our present reliance on oil is an aberration, since for most of human history we managed without it perfectly well. However, in the last hundred years or so that we have based our societies on oil, and the fossil fuels more generally,  growth in human numbers and consumption of natural resources have followed similar exponential trajectories, practically doubling the size of the human enterprise in just over 40 years. Clearly this cannot continue, and the only real choice is between making an alternative design or continuing on the present pathway of systemic collapse.

Toward the end of the film, an allusion is made to the need for living more simply, which reminded me of Part One of “The Transition Handbook: from oil dependence to local resilience”, entitled, “The Head: Why peak oil and climate change mean that small is inevitable,” and substantially involves relocalisation (deglobalisation) as part of an Energy Descent Action Plan. Indeed, much of the content of this and related “Transition” books, and beginning earlier, the work of Ted Trainer, “The Simpler Way”, offer guidance as to how we might redesign our society in order to live well while using less oil, and overall resources, ultimately getting the human species out of ecological overshoot and back in balance with the carrying capacity of the Earth.