We always have.
The Vancouver Sun reports:
The world needs an immediate reduction in the burning of fossil fuel to head off potentially disastrous effects from global warming, a prominent American scientist warned Sunday in Vancouver.
James Hansen, head of NASA’s Goddard Institute for Space Studies and an iconic figure among climate researchers, said “even the skeptical scientists now agree” that Earth is undergoing a warming trend.
Hansen told the annual convention of the American Academy for the Advancement of Science that worldwide fossil fuel combustion has pushed the average global temperature up 0.8 degrees Celsius since the 1880s, a trend that could see ocean levels rising several metres by the end of this century…