Feathers scorch if you heat them too much, so the researchers have to keep the temperature and pressure within the narrow range that make feathers malleable without burning them.
The authors say that, even if the rules are relaxed to allow emissions to a level associated with a 3C temperature rise, there will still have to be limits on fossil fuel burning.
Some climate change "sceptics" claim that this process, rather than the burning of fossil fuels, can explain much of the Earth's recent rise in temperature.
While the temperature outside was minus 30 degrees Celsius (minus 22 Fahrenheit), the wood-burning stove was cold because the family had run out of firewood, according to the welfare workers.
The dial-controlled technology and lower temperature made the oven easier to manage and allowed slices to be reheated without risk of burning bits of cheese on the cooking surface, which fouls the taste.