WASHINGTON — A government forecast says that without mandatory limits on greenhouse gases, the amount of heat-trapping carbon dioxide flowing into the atmosphere will increase by nearly 40 percent by 2030.

The Energy Information Administration made this assertion this morning in releasing a long-term forecast.

The survey projects world energy consumption growing by 44 percent over the next two decades. And it says that in the absence of limits on carbon dioxide emissions, much of that increase will continue to come from burning oil and coal.

The report said the biggest increases in energy use will come from developing countries such as China and India.

Congress is considering limits on greenhouse gases including carbon dioxide.