To avoid heating the world 1.5 °C (2.7 °F) or more above average preindustrial temperatures, climate-warming greenhouse gas emissions from vehicles need to fall dramatically — and soon.

survey published last month in the journal Climate Policy gives insight into U.S. public opinion on this change. It suggests that Americans support efforts to begin phasing out fossil-fuel-dependent cars within the next 11 years, rather than kicking the can down the road.

Conducted by a team of researchers from the U.S., Switzerland and Italy, the survey polled people in the U.S. during October 2018. It asked participants to rank pairs of hypothetical government policies according to their preferences.

Respondents preferred phase-out proposals set to begin in or before 2030 over those set for later this century. Compared to a 2030 start date, they were less likely to support phasing out fossil fuel-based transportation starting in 2020, although plans to wait until 2040 or later attracted less support than either of the earlier exits for gas-guzzling vehicles.

Nearly 70% of Democrats support a phaseout via subsidies in 2030 or even 2020, compared with around 50% of Republican and independent participants.

The survey also explored what policies the participants would like to see drive the phase-out. It found that subsidies for low-emission transportation options, such as tax credits for electric vehicles, were more popular than taxes or bans on fossil fuels. However, the survey researchers say that subsidies as a standalone policy seem unlikely to achieve the phase-out, especially on the timescale necessary. But outright prohibitions, such as those discussed in China, the European Union and California, haven’t yet been implemented. Meanwhile, taxes designed to make gas and diesel more expensive can draw opposition, as illustrated late last year when gilets jaunes (yellow vests) protestors forced French President Emmanuel Macron to reverse course on a proposed fuel tax increase.

The study’s authors concluded that subsidies are the type of policy most likely to gain support early on. While subsidies also have the greatest backing among proposals for 2030, support for bans and taxes rises if delayed until then.

The survey’s focus on the timing of fossil fuel policy comes as scientists become evermore vocal about the urgency of the climate emergency. Last year a report from the United Nations’ Intergovernmental Panel on Climate Change (IPCC) made headlines when it declared that the world had just over a decade left to take big action that could keep Earth below 1.5 °C (2.7 °F) of warming. Meeting that target, the IPCC reported, will require a 45% cut to carbon dioxide and other greenhouse gas emissions by 2030, with net zero emissions by 2050. In 2017, transportation — including cars, trucks and planes — overtook electricity generation as the largest source of U.S. carbon dioxide emissions.

One path forward, according to the study’s authors, is what they call “smart sequencing” of policies. “[A] sequencing approach that starts with introducing incentives for alternative technologies (subsidies) and proceeds with hard regulations (bans, taxes),” they write, “might obtain wider public acceptance.”

UPDATED 11.13.19: The description of the research team was corrected.