CO2 is a greenhouse gas that caused warming during past climate changes, notably as a feedback amplifying other factors

CLAIM
Increases in atmospheric CO2 followed increases in temperature. Therefore, CO2 levels could not have forced temperatures to rise.

SOURCE: Craig Idso, Robert Carter, S. Fred Singer, Heartland Institute

Published: 26 May 2017

VERDICT

Heartland Institute report’s claim that climate models are too sensitive to CO2 does not reflect evidence

CLAIM
[climate models] systematically over-estimate the sensitivity of climate to carbon dioxide ... and modelers exclude forcings and feedbacks that run counter to their mission

SOURCE: Craig Idso, Robert Carter, S. Fred Singer, Heartland Institute

Published: 23 May 2017

VERDICT

Heartland Institute report incorrectly claims no evidence of human impacts in melting ice

CLAIM
Melting of Arctic sea ice and polar icecaps is not occurring at ‘unnatural’ rates and does not constitute evidence of a human impact on the climate.

SOURCE: Craig Idso, Robert Carter, S. Fred Singer, Heartland Institute

Published: 17 May 2017

VERDICT

Global sea level rise is accelerating, despite Heartland Institute report’s claims otherwise

CLAIM
Best available data show sea-level rise is not accelerating. Local and regional sea levels continue to exhibit typical natural variability—in some places rising and in others falling.

SOURCE: Craig Idso, Robert Carter, S. Fred Singer, Heartland Institute

Published: 08 May 2017

VERDICT

The Sun cannot explain recent global warming, contrary to what Heartland Institute report claims

CLAIM
Solar forcings are not too small to explain twentieth century warming. In fact, their effect could be equal to or greater than the effect of CO2 in the atmosphere.

SOURCE: Craig Idso, Robert Carter, S. Fred Singer, Heartland Institute

Published: 03 May 2017

VERDICT

Climate sensitivity estimate given in Heartland Institute’s report is misleading

CLAIM
Doubling the concentration of atmospheric CO2 from its pre-industrial level, in the absence of other forcings and feedbacks, would likely cause a warming of ~0.3°C to 1.1°C

SOURCE: Craig Idso, Robert Carter and S. Fred Singer, Heartland Institute

Published: 02 May 2017

VERDICT

In CNN interview, William Happer incorrectly claims temperatures don’t match climate model projections

CLAIM
The temperature is not rising nearly as fast as the alarmist computer models predicted. You know, it’s much, much less, factors of 2 or 3 less.

SOURCE: William Happer, CNN

Published: 25 Apr 2017

VERDICT

In CNN interview, William Happer misleads about the impact of rising carbon dioxide on plant life

CLAIM
there's this myth that's developed around carbon dioxide that it's a pollutant […] Carbon dioxide is a perfectly natural gas, it’s just like water vapor, it’s something that plants love.

SOURCE: William Happer, CNN

Published: 25 Apr 2017

VERDICT

Boston Globe column claims that climate models have consistently failed based on no evidence

CLAIM
Climate projections using models based on it [the water vapor feedback] have consistently failed

SOURCE: Jeff Jacoby, Boston Globe

Published: 16 Mar 2017

VERDICT

Claim in New Scientist that humans are responsible for over 100% of warming is mostly correct

CLAIM
more than 100 per cent of the warming over the past century is due to human actions

SOURCE: Michael Le Page, New Scientist

Published: 11 Mar 2017

VERDICT