Drivers to shun diesel cars are responsible, in part, by an increase in the carbon dioxide emissions of new vehicles, the car industry and the commerce of the body.
The 0.8% increase, to 121 grams per kilometer, it is the first increase since the SMMT began reporting levels in the year 2000.
Diesel engines typically emit up to 20% less CO2 than petrol cars and are more fuel-efficient.
As well as the delay on diesel sales, the SMMT said that the popularity of the Suv contributed to the rise.
Suv produce about a quarter more CO2 than the smaller of the vehicles.
Despite the small increase in carbon emissions last year, the new cars now produce one-third less of CO2 emissions in total than they did in the year 2000.Diesel car sales to plunge again this yearDiesel cars: answers to Your questions
The new vehicles are much more efficient than older cars, but the 5.7% drop in new registrations, to 2.54 million in the past year shows that drivers are keeping their cars for longer.
The SMMT is calling on the government to provide a consistent approach to sales incentives and taxes to encourage drivers to purchase the cleanest cars and spend more on charging points for electric vehicles.
“Meeting of the pan-European 2020/2021 new car and van CO2 targets looks increasingly difficult, in view of the recent developments in the market and the government’s policy announcements,” the industry body said in its report.
Electric cars represent only 0.5% of the sales of new cars in the uk.
Analysis: By Victoria Fritz BBC transport correspondent
The car industry has laid the blame firmly at the feet of government for the impact of the anti-diesel rhetoric in the sale of new vehicles.
The SMMT says that is not the purchase of diesel cars, in part because the government wants tax on diesel. Consumers are uncertain about what is the true financial and environmental costs of owning a diesel could be.
Additional Factor of uncertainty about what a diesel car will have a value in the second hand market and it is no wonder new diesel sales fell 17% in 2017.
As a result, the uk is in danger of losing its climate change objectives in carbon dioxide.
A big jump in the sales of 4×4 vehicles is also part of the problem, because they are heavier and consume more fuel. Although the smaller cars still dominate the streets of britain, SUVs now account for about one of every five new cars sold.
New Suv have an average carbon emissions of 141.3 g/km, while a small car emits 115.8 g/km on average. The aim of the EU is an average of 95 g/km for all new cars sold.
Getting to the drivers to reduce the size of giant vehicles may be more difficult for the industry to get the governments back cleaner diesel or to install more charging points electric.