Is it hot in here, or are we just headed toward a global catastrophe? The Boston Globe reports: Carbon dioxide, the gas seen largely responsible for global warming, has reached record-high levels in the atmosphere after growing at an accelerated pace in the past year, say scientists monitoring the sky from this 2-mile-high station atop a Hawaiian volcano. The reason for the faster buildup of the most important "greenhouse gas" will require further analysis, the US government specialists say. "But the big picture is that CO2 is continuing to go up," said Russell Schnell, deputy director of the National Oceanic and Atmospheric Administration's climate monitoring laboratory in Boulder, Colo., which operates the Mauna Loa Observatory on the island of Hawaii. Carbon dioxide, mostly from burning of coal, gasoline, and other fossil fuels, traps heat that otherwise would radiate into space. Global temperatures increased by about 1 degree Fahrenheit during the 20th century, and international panels of scientists sponsored by world governments have concluded most of the warming probably was due to greenhouse gases.