The carbon impact of dairy butter can be more than three-and-a-half times that of its plant-based equivalents, according to a new report - with methane-producing dairy cows partly to blame. With nearly 17 billion dollars* in bread sales were made in 2019, Americans are definitely looking for something to spread on their toast. With food production thought to be one of the largest causes of global environmental change, scientists carried out tests comparing plant-based spreads and margarines against dairy-based equivalents. They found that for each pound of product, the 'mean' CO2 equivalent for plant-based spreads was 7.3lbs - compared to a staggering 26.7lb for dairy-based products. This was an increase of more than three-and-a-half times, based on analysis of 212 plant-based spreads and margarines across 21 North American and European markets, and 21 dairy butters. With the production of raw milk - the key ingredient in dairy butter - is responsible for 38% of the greenhouse gases coming from enteric emissions, in other words the methane caused by cows burping and breaking wind. In fact, just one 8.8oz pack of dairy butter equates to 2.2lbs of cow emissions (2.2lb CO2 eq). And while carbon dioxide usually gets the bad rap, methane is about 80 times more powerful at trapping heat and is responsible for 25% of global warming. The report, written by a group of scientists based on a study of Upfield's margarines, has been published in The International Journal of Life Cycle Assessment. Sally Smith, Head of Sustainability at Upfield, said: "In order to achieve emissions targets designed to limit global warming to 1.5° by 2050, there needs to be a fundamental transformation of our food system. In Western countries especially, we currently rely too heavily on meat and dairy. It is our responsibility as a forward-thinking company to understand and act to address the impact of our plant-based products on the environment. A shift to regenerative agricultural practices will be key for both arable and dairy farmers. Robust lifecycle assessments help ensure that our approach is data-driven and grounded on the latest scientific evidence. As our products generally have a significantly lower carbon footprint, use less water and less land, we have an opportunity to help people understand the impact that food choices have on the environment and therefore help them to make a more informed choice that is better for the planet." The study revealed cattle feed production and livestock rearing - including cow-related burps, farts and manure management - contributed significantly to climate change impacts, with a higher impact than most other factors. Packaging for plant-based spreads makes up 8% of its emissions compared to 1% for butter, with the latter often wrapped in a lightweight paper compared to a tub. The life cycle assessment of Upfield's margarines and spreads is in line with growing consumer attitudes towards meat, dairy and plant-based alternatives, which continue to prompt debate. It follows separate research by Dr. Hannah Ritchie, from the University of Oxford, who concluded the 'eating local' mantra was a 'misguided piece of advice' when discussing climate change. Her study revealed transport emissions are often a very small percentage of food's total emissions - only 6% globally.