• Global climate models are unable to make accurate projections of climate even 10 years ahead, let alone the 100-year period that has been adopted by policy planners. The output of such models should therefore not be used to guide public policy formulation.
• Neither the rate nor the magnitude of the reported late twentieth century surface warming (1979–2000) lay outside the range of normal natural variability, nor were they in any way unusual compared to earlier episodes in Earth’s climatic history.
• Solar forcing of temperature change is likely more important than is currently recognized.
• No unambiguous evidence exists of dangerous interference in the global climate caused by human-related CO2 emissions. In particular, the cryosphere is not melting at an enhanced rate; sea-level rise is not accelerating; and no systematic changes have been documented in evaporation or rainfall or in the magnitude or intensity of extreme meteorological events.
• Any human global climate signal is so small as to be nearly indiscernible against the background variability of the natural climate system. Climate change is always occurring.
• A phase of temperature stasis or cooling has succeeded the mild warming of the twentieth century. Similar periods of warming and cooling due to natural variability are certain to occur in the future irrespective of human emissions of greenhouse gases.
Hoffman also reproduces a chart much beloved of climate skeptics, showing actual temperature change alongside that predicted by the models. Climate hawks counter that the “missing heat” is to be found in the oceans, but there remains a remarkable disparity between the predictions of fifteen years ago and what actually happened.