Cars, power plants and other energy sources in Maryland release more carbon dioxide into the air each year than those in Denmark, Austria or Ireland, helping fuel the dangerous trend toward global warming, according to a national environmental group.

The state-by-state tally on gas emissions that contribute to the greenhouse effect, released last week by the Natural Resources Defense Council, was accompanied by a call for states to act to reduce pollution because the Bush administration has not done as much as environmental groups would like.

"States are big players when it comes to global warming," said Daniel A. Lashof, senior project scientist for the group and primary author of the report.

Many scientists fear that increasing emissions of carbon dioxide and other industrial gases are heating the globe, which could lead to thawing of the polar ice masses and coastal flooding and have drastic effects on human health, agriculture and energy demand.

In releasing its report last week, the council said states should establish a moratorium on coal-fired power plants, mandate energy efficiency in building codes and appliances, promote recycling, discourage car traffic and require utilities to implement strong conservation programs. The group also urged states to reduce use of chlorofluorocarbons for refrigeration and air conditioning; CFCs not only contribute to the greenhouse effect, but also are blamed for thinning the planet's protective ozone layer.

The report said Maryland released 68 metric tons of carbon dioxide in 1988, ranking 24th among states. If nations were included in the tally, Maryland ranked 58th in total emissions -- well behind large countries such as Canada, West Germany and France, but ahead of many other industrial nations.

Maryland came out slightly better on emissions per capita, ranking 37th among the states.

Maryland is not a national leader in reducing emissions, but has taken more steps than Virginia, said Nancy Hirsh, a policy analyst with the Energy Conservation Coalition.

Maryland last year enacted legislation providing tax credits for recycling freon, a gas used in auto air conditioners that is often released into the atmosphere during servicing. But the General Assembly killed a bill by Del. Brian E. Frosh (D-Montgomery) that would have mandated recycling of auto air-conditioning freon, and nixed several other anti-CFC measures.

Maryland has taken some actions to reduce carbon dioxide emissions that grew out of other motives. The state's recycling law, for example, requires large jurisdictions to reduce solid waste volume by 20 percent during the next three years; the aim was to save landfill space, but the effect will be to save some manufacturing energy.

Several Maryland jurisdictions have ordinances encouraging tree preservation, although only one -- Prince George's County -- specifies that one purpose of keeping mature trees is to save energy, said Susan Hedman, a University of Maryland professor who tracks energy issues for the Center for Global Change.

The Natural Resources Defense Council applauded Potomac Electric Power Co.'s rebate program to reimburse commercial building owners for installing high-efficiency lighting and to reduce commercial voltage when supplies are squeezed.

Pepco plans to pay $90 million in rebates during the next five years to consumers who install heat pumps or other energy-saving devices, and it plans to charge high-use residential customers lower rates for using appliances during off-peak hours.

The goal behind the measures, undertaken with pressure from the state Public Service Commission, is to save enough energy to avoid building one new power plant during the next decade. The state also has adopted "least-cost planning" for new energy-generating facilities, which theoretically means that environmental costs must be included in decisions on building new plants.