The report also says many similar goods are both imported and exported, adding needlessly to CO2 output in transport.
According to the BBC, over the last year, UK imports from China rose by 10 percent, nearing 6.5 million tonnes.
This is the second year that the London-based think-tank has produced an "Interdependence Day" report on the extent to which Britain's economy is tied up with imports from, and impacts on, the developing world.
Last year, the Nef found that global consumption levels pushed the world into "ecological debt" by October 9.
This year, it says, "we are in dept three days earlier."
Ecological debt means that our demands exceed the Earth's ability to supply resources and absorb the demands placed upon it.
The organisation calculates that Chinese factories produce about one-third more carbon than European ones for making the same product; and more CO2 will be produced in transporting the goods.
Two years ago, US researchers calculated that 14 percent of China's carbon dioxide emissions were accounted for by exports to the US.
Nef believes that international negotiations on climate change should move towards a system where emissions are attributed to the end user rather than the country producing the goods.
It points out that rising production of consumer goods in China and other developing countries also contributes to local pollution, depletion of water supplies, and deforestation.
It was suggested that a pricing system that reflected carbon produced in transport would be an effective way of curbing this two-way trading, by making local goods cheaper.