The report dismisses these claims with peer-reviewed evidence and concludes that “neither the rate nor the magnitude of the reported late twentieth century surface warming (1979–2000) lay outside normal natural variability,” “solar forcings of temperature change are likely more important than is currently recognized, and evidence is lacking that a 2° C increase in temperature (of whatever cause) would be globally harmful.”
“We conclude no unambiguous evidence exists for adverse changes to the global environment caused by human-related CO2 emissions,” the authors write. “In particular, the cryosphere is not melting at an enhanced rate; sea-level rise is not accelerating; no systematic changes have been documented in evaporation or rainfall or in the magnitude or intensity of extreme meteorological events; and an increased release of methane into the atmosphere from permafrost or sub-seabed gas hydrates is unlikely.”
The authors also note that “forward projections of solar cyclicity imply the next few decades may be marked by global cooling rather than warming, despite continuing CO2 emissions” and warn against using imperfect deterministic climate models to advocate for a “one size fits all” climate policy.
In light of these findings, which are “stated plainly and repeated in thousands of articles in the peer-reviewed literature” that are not “fringe,” the authors emphasize that policymakers “should resist pressure from lobby groups to silence scientists who question the authority of the IPCC to claim to speak for ‘climate science.'”