An international panel of scientists has found with near certainty that human activity is the cause of most of the temperature increases of recent decades, and warns that sea levels could conceivably rise by more than three feet by the end of the century if emissions continue at a runaway pace.

The scientists, whose findings are reported in a draft summary of the next big United Nations climate report, largely dismiss a recent slowdown in the pace of warming, which is often cited by climate change doubters, attributing it most likely to short-term factors.

The report emphasizes that the basic facts about future climate change are more established than ever, justifying the rise in global concern. It also reiterates that the consequences of escalating emissions are likely to be profound.

“It is extremely likely that human influence on climate caused more than half of the observed increase in global average surface temperature from 1951 to 2010,” the draft report says. “There is high confidence that this has warmed the ocean, melted snow and ice, raised global mean sea level and changed some climate extremes in the second half of the 20th century.”