However unpopular the criticism of economic growth, if there is to be any hope of a sustainable and equitable world the environment movement must advocate curtailing consumption to within planetary boundaries.
Consider this: can we "save the planet?"
That's a critical question if you're an environmentalist - though it requires an understanding of what 'saving' and 'the planet' means. And if those founding definitions are not based upon realistic information, what would be the result?
Beyond the clear failure of the COP21 Paris Conference to deliver a binding climate agreement, capable of stopping dangerous climate change, I believe that the environmental movement has its own policy questions to answer.
The ideas explored in this article may leave certain readers aggrieved by what I write. In the end though, the most important critic is the evidence - and today the evidence of ecological harm is at odds with many popular environmental messages.
Environmental consciousness is bound within human identity
Ever since early monotheistic religions disentangled human well-being from the ecological systems which supported them, we've been on a downward spiral of environmental destruction and exploitation - which has lead us, inevitably, to today's Anthropocene epoch.
The 'Western' environment movement, distinct from the movements of indigenous peoples with their innate bond to natural systems, began with a rejection of the apparently 'false wealth' of the 1960s consumer boom.
In the eco-political swell of the 1990s, when green politics took power and campaign groups slowly began to take corporate funding, that strong philosophical counter-argument to materialism faltered. So-called 'hair shirt' environmentalists, who continued to argue against 'consumption' in the wake of this change, were marginalised within many campaign groups.
In the neo-liberal world, political success required an engagement with capitalism in order to deliver sustainability goals; but even left-wing socialists now dismiss the the idea of ecological limits as 'collapse porn'.
Unless we embrace the evidence, what we do is PR
In the affluent world's media, messages which advocate a deeper connection of humans to the 'living Earth' are often caricatured - evoking idealistic metaphors for the developed world's spiritual dead-end which are ultimately subverted by their associated marketing message.
Ecological idealism is ridiculed - willingly consigned to the scrapheap by consumer choice.
Yet in the wake of COP21, any proposal that environmentalism can work within the economic and political status quo has abjectly failed also.
From fields as diverse as agriculture, climate and marketing, to resource depletion, ecological limits and eco-psychology - the evidence on human impacts, and how to tackle them, is increasingly at odds with popular environmental messages.
Promoting that evidence isn't being 'negative', or 'doomerish', or holding an 'outdated prejudice'. Evidence exists as it is - it is how we react to it which defines whether our advocacy is factually-based or, for want of a better description, self-deluding.
'Green' is the colour of money
Capitalism did not engage with environmentalism in order to deliver realistic change. It engaged with the environmental message in order to own and subvert it to a more profitable end.
Don't agree with that statement? The VW diesel emissions scandal is the perfect example of how that whole model of consumer-driven change has failed - leaving the consumer feeling defrauded of their good intentions.
Another, less publicized example is biofuels.
During the 1990s road protests in Britain the environment movement developed a detailed factual critique of the economic and environmental consequences of car-based transport. In the 2000s campaign groups traded that analysis for the more lucrative narrative of biofuels - which ultimate foundered a decade later when its true impacts were revealed.
For mainstream campaign groups, dependent on trying to secure members, promoting a message of alternative consumption, rather than prohibition and significant lifestyle change, is more conducive to recruiting support. But how far can you go down that route before you lose sight of your original objectives?
Right now I know of a number of people working for campaign groups, talented in their field of ecological expertise, who are focussed on membership or recruitment campaigns rather than doing the primary job of pressuring for change.
If supporting the operation of the organisation, rather than its core campaign, becomes its reason d'etre for existence, then what are these campaign groups for?
Foreseeable dead-ends subvert ecological change
I came across the issue of climate change as a scientific debate in the mid-1980s. Then in 1988 the UN set up the IPCC to study the issue further; and scientists like James Hansen began to tell policy-makers about the severity of the issue.
The IPCC's first assessment came out in 1990. Then in 1992 the United Nations Framework Convention on Climate Change (UNFCCC) was signed at the Rio 'Earth Summit'
Then... not a lot happened.
The whole process has been chasing its tail ever since.
One stark message to come out of COP21 was the extent to which, on the debate over ecological decline, the movement censors itself. If they were to "speak truth to power" they would no longer be welcome in the room.
Major aspects of climate policy, such as emissions trading, have been shown to contribute a negligible amount to reducing greenhouse gas emissions. And yet many within environmentalism cling to such ideas in order to deliver change without threatening 'business as usual'.
The climate battle is lost without a critique of economic growth. Look at this graph - (above right). It shows the US Carbon Dioxide Information Analysis Center's (CDIAC) estimates of greenhouse gas emissions from fossil fuels since the beginning of the Industrial Revolution - from 1751 until (on provisional data) 2012.
Over 261 years of industrial and technical development, under CDIAC's dataset, humanity has generated 383 billion tonnes of carbon emissions from fossil fuels (note, 'carbon' - the weight of carbon dioxide is 3.667 times greater).
The emissions of carbon since we decided this was a global problem in 1992 have been 152 billion tonnes.
In other words, over 261 years of historic emissions, we've emitted 40% of the total in the 20 years since the world decided we had to tackle this urgent problem. In 20 years annual emission rates have risen almost 60%.
Why the large change, even though technological efficiency has been increasing over this time? Economic growth.
It is not simply 'consumption' which is the issue, or what form that consumption takes. Any measure of growth in the human system, for simple reasons of thermodynamic reality, will create a change in material consumption - and thus the energy required to enable that activity to take place.
The reason the UNFCCC process has stalled isn't simply that climate deniers have befuddled policy-makers. The entire economic process is based upon a myth of growth, and an existential terror that without growth human society as we know it would collapse.
Green technology can't displace the 'service' of fossil fuels
OK - if fossil fuels are a problem, let's switch to renewable energy.
This is reason why the green technology/green consumer argument is so seductive in policy-making fields. It allows a theoretical change in damaging impacts without changing society's dependence upon material consumption and growth.
Problem is that whole argument - like VW's engine management system - is another deception. Not least because while the energy produced might be physically equivalent, irrespective of price the comparative investment returns of these processes are lower than conventional fossil fuels.
Many environmental groups, in their efforts to lobby politicians, love these simple solutions too.
Unfortunately most of their plans for change - for example CAT's Zero Carbon Britain - while they may be balanced in terms of their energy calculations, do not take account of the resource limitations of making them happen. Not simply the resources required to build the energy infrastructure, but also the additional resources involved in society utilising that energy.
Right now there is a growing concern amongst academics and industry figures that the specialised resources required to build 'green technologies' on a large scale might not exist. Even conventional resources, such as copper, have their own unique limitations. And while in most cases there are substitutes available, they often have their own limitations or prohibitions on use.
For example, the large, direct-drive wind turbines which are the core of expanding wind power are reliant on the use of rare earth metals such as neodymium and samarium. These metals have a limited supply - which limits the roll-out of wind power well below the theoretical wind resource available. What's more the production of those metals is having a severe, toxic impact upon the environment and indigenous communities.
On-line environmental activism: a dissonant practice?
One of the largest shifts in environmental activism in recent years has been in the area of on-line activism.
When you buy a new laptop or smart-phone, roughly 90% of the ecological footprint of that device has already been expended through the production and supply chain. For example, just to make the memory chip of a laptop takes more energy than the device will consume over its average service life with the user.
The ecological footprint of the Internet, which has become essential to the use of many technologies, now exceeds the footprint of that other icon of green angst, global air travel. That trend in consumption has been exacerbated by the recent shift towards 'the cloud'.
There are many practical ways to address the issue of impacts of IT. The industry could make devices which last many years, drastically cutting their life-cycle ecological footprint. That, however, is not on the agenda because it would entail a significant contraction in, and loss of revenue from the whole tech sector.
Climate change is not 'the worst' of all ecological evils
It is not simply that the mainstream of the environment movement fails to call for 'degrowth'. From my own experience, they are vehemently opposed to espousing any line which directly challenges the the political fetish of growth.
Unfortunately the often-used substitute, that 'less is more', fails not only on thermodynamic grounds, but also because it disregards the material differences between 'quantity' and 'footprint'.
As outlined earlier, monotheist religion erased the 'spiritual' link of humans to their environment, rendering it expendable in the name of human need or greed. In the same way, the mainstream environment movement has lost its way by simplifying to a single-issue, 'monotheist' belief in climate change - to the exclusion of other, arguably equally deleterious trends in human development.
For example, intensive farming requires fertilizer. While the media often looks at nitrogen, of equal significance is phosphorous. Right now there's a growing concern about the future supply of phosphorous, and what that means for global food supply within the next 20-30 years. But continuing our use of phosphorous is not an option either as it causes significant damage too.
There are alternatives, specifically agroecology or permaculture. Problem is the 'business as usual' lobby don't like these because it requires abandoning the current system of intensive commodity agriculture, with their concentrated ownership and control over production and markets.
That's why tackling climate change is attractive to the 'business as usual' lobby - it's a product which can be sold because it entails using more equipment and energy to solve pollution. That's also why tackling climate change alone will not avert the ecological collapse of human civilisation during this century.
The 'big lie'
The greatest myth of the consumer society is that modern lifestyles are 'normal' - and this can continue forever because we're clever little apes who can solve any problem.
That hubris, in the face of insurmountable ecological limits, will be our collective downfall.
Dismissing the reality of ecological limits will not make the problem go away. The mainstream environment movement's overbearing focus on climate change not only makes society ignore many equally critical ecological issues, it also leads people, against the current body of research evidence, to advocate very silly ideas.
However unpopular the issue of criticising economic growth, and however unpopular that makes environmentalists with the leaders of the affluent world, if there is to be any hope of a sustainable and equitable world the environment movement must advocate curtailing consumption to within planetary boundaries.
Of course, you don't have to wait for everyone to agree on that to begin. You can make a personal start to 'degrowth', minimising your own ecological footprint, today. And for that conviction, if you are excluded from the doors of power you always have the option to sit outside.
Paul Mobbs is an environmental and peace campaigner. He runs the Free Range Activism Website (FRAW) and is the author of Energy Beyond Oil and A Practical Guide to Sustainable ICT (which is available free on-line).
For a fully referenced version of this article visit the FRAW site.