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Showing posts with the label observational evidence

Observational Evidence for the Greenhouse Effect

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In a previous post I looked at evidence of the greenhouse effect from empirical data. In short, an analysis of empirical data for CO2 and GMST shows a one-way causation with CO2 causing warming since the mid-twentieth century. This paper conclusively establishes causation from empirical time series of CO2 and temperature. That is, not only is CO2 a good predictor of temperature, but  uncertainty is reduced in future values of temperature given past values of CO2. This evidence is conclusive, but  even without this, we have observational evidence for the greenhouse effect. In this post I want to consider how this is true generally in satellite observations of earth's emission spectrum at the top of the atmosphere and in individual studies that have made observational determinations of the greenhouse effect. General Observations The graph above quite literally shows the greenhouse effect. This can be readily determined, but we need to begin by calculating the effective temperat...

How Do We Know that Increasing CO2 Causes Warming?

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This is part 1 of a two part post. The evidence that increasing CO2 causes air temperature to warm began to accumulate as far back as the 1850s with studies from William Tyndal l[1][2] in the UK. Tyndall's experiment can be roughly replicated in high school lab classrooms with pretty simple experiments, some of which are demonstrated on YouTube. Estimates of climate sensitivity to increasing CO2 can be found in the works of Arrhenius[4] in the 1890s and Plass in the 1950s.[5] The landmark work of Manabe in 1967 successfully modeled the effects of increasing CO2 on the climate system. His study produced theoretical predictions that have been observed ever since. Especially since the satellite era, for instance, scientists have observed that the stratosphere is cooling while the troposphere is warming, just as Manabe expected. In the 1970s, scientists arrived at an estimate of equilibrium climate sensitivity[7] of about 3 C; an estimate that still continues to be at the center of sc...