The Green Tau: issue 20

Biodiversity and food production 

Last week’s Green Tau weekly began a mini series looking at biodiversity. We noted that despite the relative smallness of humanity in terms of global biomass, we humans are dramatically and drastically altering the planet’s biodiversity. This week I want to look at the impact food production has on biodiversity. 

Over the millennia humans have domesticated both animals and plants, selecting and breeding species, and developed farming practices that would best provide food. In the process, humans extended their control over land that had previously been wild, which in turn has limited the land available for wild animals and plants. 1000 years ago, less than 4% of habitable land was farmed. This increased over the centuries, and particularly so from the mid 1800, when the area of farmed increased from under 25%  to the current 50%. (Habitable land is land not covered by glaciers, 10%, nor barren land such as deserts, sand dunes, bare rock, salt flats etc, 19%). In Europe the area of farmed land is now declining slightly, whereas it is continuing to expand in Africa, Asia, China and parts of South America.

Currently there is much media coverage about the clearance of the rain forests in Brazil to create new agricultural land plus accompanying access roads. This process destroys unique habitats with the loss of many plants, animals, birds and insects etc. It also destroys the millennia old way of life of indigenous people.  It is easy to see how such expansion of farming land exacerbates biodiversity loss. The same problem also arises in Africa, Asia and China. Mangroves have also been cleared to make way for shrimp farms, palm oil plantations and rice fields. 

A perhaps previously ignored consequence of expanding farming into previous areas of wilderness, is the increased contact between wild and domesticated animals. This allows diseases to spread more rapidly between the different species. What might be an insignificant virus infecting a wild animal can become a highly infectious virus in domestic animals. These virus can then spread to humans. Such zoonotic diseases include the Ebola virus, SARS and the current Covid 19.

Over the millennia, much of the UK has also been deforested to make way for farm land. Tree coverage  in the UK stands at about 12% which is much lower than most other countries in Europe. Top of the league is Finland with over 50% tree cover; Spain and Portugal are around 35%; France, Germany and Switzerland around 30%. As trees provide a great many habitats for other plants, birds, animals and insects, as well being good stores of carbon, the government’s climate advisers now recommend  tree cover should be increased to 17-19%. As well as planting new trees, it is also important that existing trees are protected: it takes many years for a tree to reach maturity and whilst they are still saplings they do not provide much habitat for other wild life. 

It is not only trees that have been cleared to make way for farming in the UK. Wetland areas such as marshes and bogs, have been drained. This destroyed the unique habitats of many different plants, insects and animals. In the same way, clearing hedgerows has had a detrimental affect on biodiversity. There is now a growing awareness of the importance of restoring and maintaining a diverse range of habitats to support different plants and creatures. Where the area of a particular habitat becomes too small, it may fail to maintain populations of plants and creatures at a viable level. However creating a corridors between habitats enables larger populations to be supported. Hedgerows perform this task on a small scale, as can railway lines and road verges.

Not only has farmland been expanding over the centuries, but what is farmed has changed. Increasing global trade, colonialism and the intensification of farming, has produced a agricultural system that now grows a very limited number of plant species. Two thirds of the world’s food comes from just nine plants: sugar cane, maize, rice, wheat, potatoes, soybeans, oil-palm fruit, sugar beet and cassava. 

Such a concentration makes our food supply vulnerable to the effects of climate change and diseases. This year’s durum wheat crop has been much reduced because of  exceptionally dry conditions in Canada (the harvest is down by a third) and wet ones in Europe. Nearly half of all the bananas grown in the world are one variety, Cavendish, even though there are approximately 999 other varieties. The Cavendish banana is now threatened by a fungus which could wipe it out.  

This over concentration on a limited number of species has meant that many local and older plant varieties have been marginalised – another form of biodiversity loss. However the value of such plants is now being recognised. They can provide alternative crops better suited to local growing conditions and/or changing climatic conditions. Such species include quinoa, which  can be grown at high altitudes, teff which like quinoa can be grown at high altitudes and where water supplies are limited, millet which can tolerate high temperatures, and einkorn which needs less nitrogen – ie can grow in less fertile soils – than wheat.

The same pattern of concentration occurs in animal farming too. Nearly all the world’s diary cows are based on one single breed, the Holstein. As with arable crops, there are advantages of protecting and promoting rare and ancients breeds of farm animals. But in terms of biodiversity what is more incredible is the sheer biomass of farm animals. They account for 60% of all mammals on the planet (of which cattle and buffalo  account for 40%); we humans account for 36% whilst the remaining wild mammals a mere 4%.

Globally 77% of agricultural land is used to raise livestock. This includes land used to grow animal feed. Yet this 77% produces less than  20% of the world’s calories. Land used for livestock could be better used to produce plant based food that would feed a greater number of people and/ or rewilded to increase biodiversity. Factoring in the carbon footprint of livestock, especially cattle, there are even more benefits to be gained from reducing livestock levels. 

Eco Tips

Keeping Warm in Winter

  1. Wear layers of clothes. Each layer will trap air that is warmed by your body. Every layer is another layer of insulation. 
  2. Wear thermal underwear or alternatively wear extra leggings and T-shirts which will be save  having to buy extra clothes.  
  3. Outside wear a hat, gloves and scarf – and why not do the same inside? Historically people have often worn hats inside – neat bonnets, Tudor caps,  Monmouth caps, smoking hats, head squares and scarves, beanies and berets. 
  4. Cosy socks and slippers are pluses too – make sure your winter shoes and boots are big enough to allow for warm/ thick socks. If you have thins socks, double up and wear two pairs.
  5. Close curtains and pull down blinds at dusk for once  the sun sets, temperatures will drop. Drawing your curtains will keep the warmth in the room. The more layer between you and the outside, the better the insulation. You might have blinds and curtains for example. Alternatively you can get extra thermal linings to hang behind your curtains. 
  6. If overnight your bedroom has remained warm, allow that warmth to permeate the rest of the house before opening the windows to air the room.
  7. If windows are draughty, you can seal the gaps with a proprietary stick on strip.  
  8. If your doors are draughty or if they are not very thermal efficient (maybe with lots of glass) you can hang a curtain to pull across at night time. You can make a sausage shaped door stop  to prevent droughts that come under a door, or if it is an external door you could fix on a draught excluder. 
  9. Take exercise – it will warm you up. If you get cold through sitting still, even running up and down the stairs a few times will help. 
  10. Wrap up well and have a brisk walk. 
  11. Have plenty of hot drinks and at least one hot meal a day. 
  12. Use a hot water bottle in bed – you can also use one if you are sitting down for a while, either under your feet or on your lap. Equally if you are sitting still for a while, have a blanket to put over your knees. Or if you are watching TV you might  wrap yourself in a blanket.
  13. Make a hand warmer – this could be a cotton bag filled with uncooked rice  that you heat for a few seconds in a microwave. You will find plenty of DIY instructions on line. Or you could use a small heat resistant bottle or jar, fill it with hot water and wrap it in a sock. 
  14. Our own body heat will  heat up a room. Plan your day so that you spend most of it in one room rather than heating up several spaces. 
  15. With all these measures, you should be able to turn your thermostat down so reducing your carbon footprint. Similarly use the controls on your heating to limit the number of hours you need the heating on. During the day, especially if the sun is shining, or if you are active, you will not need extra heating.

Green Tau Reflection

This week saw a stand off between Christian climate activists and the clergy in St Paul’s cathedral over the Church of England’s continued investment in companies profiting from fossil fuels. It has distressed me greatly.

Woe to you … you tithe mint and rue and other herbs, and neglect justice and the love of God; it is these you ought to have practiced, without neglecting the other. (Luke 11: 42)

Medicinal Plant Herb Bee Pasture Plant Mint Plant

Is it that the Pharisees that Jesus was addressing have become so bogged down in the minutiae that they can’t see the bigger picture? Had they become so concerned that all the ‘t’s be crossed and the ‘i’s dotted that they could no longer read what the writing said? They could only see the spelling mistakes but not the story. 

Is it that they found it is easier to address the needs of personal hygiene than issues of  social justice, poverty and victimisation that were prevalent ills of the world in which they lived? Did they find it easier to keep washing their hands before meals than to address the luxury lifestyle enjoyed by Herod Antipas at the expense of the rural poor.  

Is it that by observing the smaller and easier religious requirements, that they could to all outward appearances be seen as upright exemplars of their faith and so earn the honour and respect of their fellow believers. Perhaps the observances of small things gave the impression of great integrity – if they so routinely practice these small religious acts how much more must they be observing the full law?

Yet Jesus sees through the outer show. He has seen that inside the polished exterior they are full of greed and wickedness (Luke 11:40). He is critical of them for their lack of love and disregard for justice. Whilst they have sought the best seats in the synagogue and respectful greetings in the market place, Jesus has been focused on the work of feeding the hungry, healing the sick, releasing the imprisoned, validating the forgotten, turning social expectations upside down, calling for a turning away from unsustainable lifestyles – and bringing in the kingdom of God. 

Jesus and his disciples knew from experience that doing God’s will meant getting hands dirty, getting down alongside the sick, withstanding jeers, taking the lower place, and ultimately to be self sacrificing. Such a lifestyle is not always easy, and do we not all want some degree of love and respect? Yet equally experience tells us that if we have confidence in God, even when we are ill-treated, scorned, marginalised, we will still find joy in doing God’s will.

Notice that in Jesus’s reply he reminds the Pharisees that doing the small things should have been an ‘and also’ to the exercise of love and justice. Paying attention to the small things as well as the large is about integrity. For this reason we see Jesus coming to be baptised alongside his fellow country folk. We see Jesus going regularly to the synagogue and taking his turn to read the scripture. We see Jesus observing the traditions of Passover. But for Jesus outward actions do not take the place of an inward commitment to the kingdom of God. 

At the present time the single most overwhelming disaster facing the world – God’s world – is human-made climate change. The effects of the rise in global temperatures is already being felt, and the accelerating affect that ongoing temperature rises will create is predictable. Plants and creatures unable to adapt are rapidly becoming extinct. Humans too are struggling and failing to adapt.

The elderly cannot readily cope with extremes of temperature and death rates are rising. The poor cannot afford to adapt their homes to improve insulation levels nor can they afford house insurance against flooding and fires as these becomes more frequent. Not can the poor readily move to more amenable climes. Islanders and those living along river deltas cannot stop rising sea levels from destroying their homes. Farmers cannot adapt practices quick enough to cope with extreme weather conditions. Young children cannot survive as drinking water supplies dwindle to nothing.

All this because we did not pay heed to the warnings, we did not stop polluting the atmosphere with more and more carbon dioxide. Instead we have kept our focus on our everyday habits – school run refuel the car, laundry in the tumble dryer, Sunday lunch roast beef, half term holiday in the sun- and ignored the long term direction of the climate crisis. We have not wanted to admit our responsibility for climate change, not even accepting that we might have been unknowingly guilty of causing harm. Nor have we wanted to change our lifestyles, our habits of a life time – to forgo our metaphorical seats in the synagogue – or loose the respectful comfort of western citizenship.

Surely, we said, this problem is so big it must be a problem for governments, big businesses and world organisations to deal with? It must be their responsibility not ours. And if they act as if there is no emergency, no urgency to act, should we not follow their lead and let things sort themselves out?

We are happy to do the small things, to reuse our plastic carrier bags, recycle the newspapers, buy an eco friendly hammock for the garden and make sure our new T-shirt is made from organic cotton. But to address the big problem, to seek love and justice for the earth and all its inhabitants, is beyond what we can even imagine. 

But in the background there have been people calling for and working for change. People who see the problem for what it is and see the scale and urgency of the changes needed. People who are prepared to stand up and stand out and say it like it is. 

And where in all this is the church? Where in all this are those who are followers of Christ? Where is the leadership, the penitence, the will to turn things round? Why are we still counting out our tithe of mint and rue whilst supporting a vast carbon producing, fossil fuel dependent economy?

Count Down


 Action 8: The climate crisis is affecting the whole world. Sometimes in the UK it can seem as if the effects of the crisis are minimal – although recent flash floods and heat waves are changing this -so why not  choose a country somewhere else in the world -eg in the Pacific or the Arctic – and find out how life there is being changed.

Far away and near at hand

The floods were far away

Now there near at hand. 

How long before I wet my feet 

and take a stand?


The heat was far away.

Now it’s close to home.

How long before I own the fact 

and finally begin to act?


Hurricanes were tropical.

Now they’re topical.

How long before I feel my guilt 

and understand the world we’ve built? 



Our climate is changing –

Far away and near at hand. 

Holy God, redeem our failings

and strengthen our resolve:

far away and near at hand.

The Green Tau Issue 7 11th July 2021 Are extreme weather events here to stay?

Extreme weather conditions – floods, droughts, wild fires, heat waves, hurricanes, blizzards -are now more frequent and more severe. 

http://www.max pixel.net Orange Heat Danger Blaze Smoke Blazing Wildfire

The energy that creates weather comes from the sun. The sun’s heat warms land, sea and air where differences in temperature create ocean currents and air currents – winds. When air moves across the seas it picks up moisture which ultimately becomes rain. The hotter the air the more water is taken up and held in the air. Again heat becomes a determinate of rain fall patterns – both quantity and intensity of rain fall (or snow etc) – eg monsoons in India after their hot season.

Air, land and sea are all heated directly by the sun. They are also heated indirectly by radiant heat from the earth. During the course of a day, in the absence of cloud cover, air temperatures will rise further as the heat from the sun is supplemented by heat radiating back from the earth. If the lack of cloud cover persists overnight, the radiant heat is lost into the upper atmospheres and the air temperatures drop. If however it is a cloudy night, the cloud will act like insulation keeping in the warmer temperatures. 

Given that the sun has always been there, why are temperatures now increasing at a rate that are creating extreme weather events? 

The Earth’s atmosphere is a mix of oxygen, nitrogen, carbon dioxide plus smaller quantities  of other gases. Of these carbon dioxide is particularly good at absorbing heat and thus preventing extremely low temperatures when the earth’s surface is not receiving direct sunlight. Since the beginning of the Industrial Age we humans have been burning increasingly large amounts of fossil fuels such as coal, oil and gas. As these burn they release carbon dioxide. As levels of carbon dioxide in the atmosphere have increased so the insulating effect has also increased, and with it global temperatures – and with that an increase in extreme weather events.

Global annual average temperature (as measured over both land and oceans) has increased by more than 1.5°F since 1880 (through 2012). Red bars show temperatures above the long-term average, and blue bars indicate temperatures below the long-term average. The black line shows atmospheric carbon dioxide (CO2) concentration in parts per million (ppm), indicating a clear long-term global warming trend.

(Figure source: 2014 National Climate Assessment, updated from Karl et al. 2009)

The UN reported that across the world, between 2000-2019, there were 7,348 major disasters, claiming 1.23 million lives, affecting 4.2 billion people and causing £2.3tn in economic losses. Whilst in the UK flooding affected the Midlands and northern England in 2019 after the wettest November on record, and again in 2020 affecting Wales and southern England. The freezing temperatures of the ‘Beast from the East’ in February 2018 were followed by a heat wave from May to July with wild fires in areas near Manchester. 

Since 1950 carbon levels in the atmosphere have risen from 311 parts per million to the current level of 414 ppm whilst average global temperatures have risen by just under 1C. The Paris Agreement set out to keep global temperature rises below 2C max and ideally below 1.5C, requiring  global carbon dioxide emissions must be reduced to net zero by 2050. As this is not going to reduce temperatures below where they are now, extreme weather events are something we have to accept and adapt to. 

Adapting to our new climate is one issue that will be addressed at the COP26 climate conference. It is also something that we can work at too. Insulating homes not only keeps them warmer in colder months, it also keeps them cooler in hot months. Win win plus reduces energy needs for cooling / heating. Planting trees creates shade and because of the way they ‘breathe’ reduce temperatures further by absorbing heat. In Rotterdam a 10% increase in tree cover produced a 1.3C reduction in temperatures ( Klok et al. 2012). Trees also lock away carbon dioxide and slow the rate at which rain water fills soils and drains so reducing the risk of flooding. A further win win solution.  

Urban areas heat up faster than others because they have large areas of concrete and tarmac which readily radiate the sun’s heat back into the atmosphere. Reducing these or replacing them with grass or vegetative cover again reduces high summer temperatures. Creating cool areas around buildings with verandas, planting in trellises and planting in general will cool the air coming into the buildings as well as providing areas of shelter from the heat.