Germany, Latvia and Sweden miss 1.5C by 2050 in Stephanie Cap's scenarios, even with cleaner industry

The household footprint in Cap's work is built from spending. Her scenario models use the EXIOBASE database to map the carbon footprint of households ^[5]. She described what that means for a single purchase: "If you buy vegetables, a laptop or electricity, the model looks at all the production factors involved in producing that product. For one euro's worth of food products or train travel, for example, I can calculate how many greenhouse gases were emitted in the process." ^[6] The emissions from making a product are charged to the household that buys it, so a change in what people buy shows up in the footprint.

Every scenario already assumes industry becomes far more sustainable ^[8], and the household portfolios sit on top of that ^[7]. The participation figures therefore measure what households must add once industry has done its part. The model does test this half of the argument, and Cap put it plainly. Cleaning up industry "is not enough on its own", she said, "and neither is making households more sustainable. We really need both." ^[3]

Each percentage is a share of the whole population adopting a wide range of changes ^[9]. The split between countries is large. The higher emitters need about 27 to 37 percentage points more of their people on board in 2030 than Spain and Hungary do ^[2]. The two countries with the lower 2030 thresholds are also the only two that can still reach the target in 2050 ^[1].

These are exploratory scenarios. They are built on a 2015 baseline and on decarbonisation pathways developed several years ago ^[13]. Cap said this does not diminish what they imply about the scale of lifestyle change and decarbonisation needed ^[14]. I think that holds for the direction of the result. The exact thresholds are less secure, because every one of them is computed from that 2015 starting point.

Cap's second claim, that businesses and governments must create the conditions for these changes, is of a different kind. She argues that uptake is not simply a matter of willingness, and that relying less on a car is hard without good public transport or working hours that make it realistic ^[15]. The scenarios were built to answer what happens to emissions if households change their consumption ^[18]. The share of people taking part is the thing that varies ^[9]. The scenarios do not show what would get 87% of a country's people to take part, or which policies would do it. In my view her argument is plausible, and thresholds this high make it hard to set aside. It is still her reading of the numbers.

She hopes the findings renew the sense of urgency among EU policymakers, with a stronger push for emission-free heating, transport and individual lifestyle change ^[16]. "I understand that it can feel overwhelming when you look at the gap between where we are now and where we need to be," she said ^[17]. "I hope people feel empowered to make changes, knowing that they really can make a difference." ^[17]