One of Merton's wildflower meadows

Sustainability and Biodiversity

"Merton College has a rich 757-year history of responsible stewardship of historic buildings, farmlands and the environment. This is in addition to our excellence in academic teaching and research. I am proud to be the Warden of a college community so committed to improving biodiversity and creating a sustainable future. These are challenging times for us all, and Merton College is playing its part in various and innovative ways. Please enjoy reading how we are meeting these challenges and follow our journey as we continue to deliver through our governance a biodiverse, sustainable and zero-carbon environment."
Professor Irene Tracey, Warden

Measuring what we do

Merton has used the services of a specialist energy surveyor to audit the College estate in terms of carbon, natural capital and biodiversity - this was in conjunction with a University research project run by the Oxford Partnership for Operationalising the Conservation Hierarchy. We have also worked with a specialist external energy advisor with expertise in historic buildings to assist in reviewing our carbon footprint, identifying opportunities for carbon reduction, developing policies and increasing college-wide awareness through improved reporting and communication.

One early outcome has been the replacement of many of our manually-read electricity meters with Automated Meter Reading (AMR) equivalents, meaning energy consumption is now being accurately recorded with consumption data available via a web portal.

Making our buildings more energy-efficient

Merton has an ongoing programme to replace baths with shower facilities in student and Fellows’ accommodation, and we will be fitting a high-efficiency Megaflo hot water storage system as part of our refurbishment programme.

The TS Eliot lecture theatre hall, which makes extensive use of natural light
The TS Eliot lecture theatre hall, which makes extensive use of natural light


The TS Eliot theatre building employs rainwater harvesting, makes extensive use of natural lighting, and has an adiabatic heating and cooling system in the main theatre hall; the building has been awarded a BREEAM Excellent Rating. We use the cloud-based platform eco-sync, which allows room-by-room control of heating and will synchronise room bookings with heating control; this has resulted in a 20% reduction in gas use.

Switching to electric

We have significantly reduced energy usage in our kitchens through the replacement of gas hobs with electric induction hobs.

We have upgraded washing machines and fridges to A+++ standard, resulting in energy savings due to reduced power and water requirements.

Traditional incandescent lighting is being replaced with LED equivalents in both college accommodation and the Chapel. Lighting controls and timers have also been fitted.

The College has installed electric car charging points in one of its car parks - the charging points are used daily, and we plan to install further points in our other two car parks.

Reducing consumption

We always look to install or upgrade draught-proofing and insulation in our buildings when they are being refurbished: two recent projects involved the installation of insulated exterior cladding and double-glazed windows, both effective means of minimising heat loss. Our multi-year refurbishment of student rooms has involved replacing and upgrading windows, installing high efficiency electric heating, LED lighting and centrally stored hot water systems. The combination of installing high efficiency glazing and low energy, controllable heating has been very beneficial. Having large centralised hot water systems as opposed to local point-of-use heaters has also made buildings more energy efficient and controllable.

We have installed a voltage optimiser/step-down transformer, reducing energy consumption by 15%.

The installation of modern Thermostatic Radiator Valves (TRVs) has allowed us to improve thermal efficiency.

All toilet cisterns have water-saving devices fitted. The main plate-washing machine in our kitchens has a recycle facility to reduce water consumption.  

Recycling and reducing waste

Recycling is carried out widely across the College, to minimise waste being taken off-site. We provide separated recycling bins in accommodation, offices and communal spaces. Confidential waste paper is shredded and recycled. We recycle printer cartridges, pens, and batteries. Garden waste is composted and reused.

Digitising processes, for example providing committee and meeting papers in electronic format, has successfully helped us to reduce our paper waste, as well as reducing the administrative load on staff.

We have reduced single-use plastics in packaging, and introduced 100%-recyclable cups for all our in-house coffee facilities.

Cutting food waste

We run a food waste recycling scheme from our main kitchens, and send food waste to a local anaerobic digestion plant (Cassington AD facility) where it is converted into green energy and a bio-fertilizer which Oxfordshire County Council uses on its gardens, green spaces & parks. This initiative is supported through the provision of food caddies and signage in our dining hall.

Most meals are pre-booked to avoid waste and we have portion control at the food servery. Where possible in accordance with safety requirements, the Kitchens team recycle leftover food in other meals.

Sustainable sourcing

Our Kitchens team, led by Head Chef Mike Wender, make great efforts to ensure that the food we serve is sustainably sourced: this includes using local seasonal suppliers, Fairtrade/Rainforest Alliance suppliers for coffee, MSC-certified fish (mainly caught by locally owned & crewed day boats - we never buy fish from factory trawlers - and bought from Brixham Fish Market in Devon), and ethical sources for palm oil and many other products.

Food being prepared in Merton's kitchens - Photo: © John Cairns - www.johncairns.co.uk
Food being prepared in Merton's kitchens - Photo: © John Cairns


We buy as many ‘in season’ British fruits & vegetables as we can. The eggs we use are all free range, and come from Mayfield Farm – only 15 miles from the College. We buy much of our meat from Aubrey Allen Butchers, recent winners of the National Meat Buyer of the Year award for ‘Ethical Sourcing & Animal Welfare’ and plastic-free business champions. Our genuinely free range pork is Blythburgh Pork from St Margaret’s Farm in Suffolk. Most of our poultry comes from Robert Caldecott who runs a third-generation farming business in Worcestershire producing high welfare free range chicken and turkey.

Promoting sustainability

We have a Green Impact group which involves Fellows, staff and students in promoting sustainably focused work. The group meet on a termly basis and report on their activities at staff briefings. Their work has been recognised with the Oxford Sustainability Green Impact Bronze Award. A sustainability workshop is planned to enable us to think collectively as a College what we can and should be doing.

Merton is part of the Conference of Colleges Environmental Sustainability working group, which published its report on existing college sustainability initiatives in May; we continue to work with other colleges across Oxford to share details of existing and planned sustainability initiatives.

Investing sustainably

“In 2020, as part of our focus on sustainability, we moved the entirety of our developed market listed equity portfolio to an ESG tilted tracker. The change reduced the carbon emissions intensity of the portfolio by over 40%.”
Charles Alexander, Finance Bursar

Last year the College sold all of its developed market listed equity holdings in L&G’s index funds and reinvested the proceeds in L&G’s Future World ESG Developed Market Index Fund. This move has significantly reduced the carbon emissions intensity and carbon reserves intensity of the College’s listed equity holdings, and ensured that the College’s listed equity investments have no exposure to pure play coal miners, manufacturers of controversial weapons and companies in perennial breach of the UN Global Compact.

Biodiversity and Sustainability across the College's estates

"Completing the natural capital and biodiversity audit of the College Estates will be an important step in developing our carbon strategy. It will allow us to model the effects on overall carbon production of changes to our estate management strategy or the introduction of new projects such as renewable energy schemes, and thus our ability to offset carbon produced elsewhere in the College. The audit will also highlight areas where we can make changes that will improve biodiversity on our estates."
John Gloag, Estates Bursar

The College is about to complete a natural capital and biodiversity audit of its external estates. This will provide a baseline on the carbon footprint and biodiversity throughout the College’s estate, based on the current use and occupancy.

We have reviewed all of the College’s rural estates with renewable energy operators to test their suitability for renewable installations.

Heads of Terms have been agreed for an Option Agreement on a 200-acre solar installation in Surrey. Terms have also been agreed for an Option Agreement to lease land in Surrey for a battery storage site capable of storing between 100-150 megawatts of electricity.

The Estates Bursary is in negotiations with the farm tenant for the surrender of a 340-acre farm, and are considering various farming options to switch from agricultural production to improve the natural capital on the property through either extensification, tree planting, and no/low input management regimes.

All new tenancies are being reviewed to include drafting to encourage occupiers to consider opportunities to improve Biodiversity Net Gain and reduce carbon production.

Wildflower Meadow Restoration Project

Merton’s meadows are being managed for the benefit of wildflowers with the aim of creating a flower-rich grassland. The meadow ecosystem attracts a multitude of wildlife and supports flora and fauna that could not survive in other habitats.

Working with the Thames Valley Wildflower Meadow Restoration Project, the Gardens team, led by Head Gardener Lucille Savin, are hoping to restore two areas, Great Meadow and Music Meadow, to connect up with other wildflower meadows around Oxford and help to create a network of green spaces.

50% of the area has been oversown with ‘green hay’ (hay containing wildflower seeds) from a local donor meadow. This included seed such as yellow rattle, which is semi-parasitic on grass, and in future years will reduce the vigour of the grasses, giving more space for the wildflowers.

A hay cut each summer removes most of that year’s growth, reducing the fertility, providing favourable conditions for wildflowers over grasses. The hay is used by local farmers and contributes to 21st century agriculture.

The team hope to see an increased richness and abundance of wildflowers over the coming years. This diversity will change annually according to weather patterns meaning meadows are good at adapting to climate change and the predicted anthropogenic global warming.

Meadows are particularly effective at sequestering carbon and could play a valuable role in the current ecological crisis. Species have varying root depths which can take carbon down to 1½ metres below ground, where it is locked up whilst the soil is left undisturbed.

The Gardens team will be monitoring changes to flora and insect diversity, and aim to report on how the project is progressing in future.