We predict the future when we publish the time for sunset and sunrise, the time for high and low tide, and the time for the equinox and solstice. The basic laws of physics allow us to accurately determine each of these events long before they actually happen. These predictions require knowing the orbit of the moon around the earth and orbit of the earth around the sun. These orbits vary and the earth wobbles on its axis over time so there is some uncertainty and adjustments are made over time to the values listed above.
The basic laws of physics apply to global climate. We can predict the future average temperature of the atmosphere using physics just like we can predict the movement of the sun and moon. Denying that global climate can change is like denying that the moon orbits the earth and the earth orbits the sun.
The greenhouse effect was discovered by Joseph Fourier in 1824, first reliably experimented on by John Tyndall in 1858, and first reported quantitatively by Svante Arrhenius in 1896. The greenhouse principle was developed as a theory and verified by experiment more than 110 years ago. The basic laws of physics used to predict global climate change include the Stefan-Boltzman law and Kirchhoff’s law.
Over time, greenhouse gases like CO2 can have the same effect on the atmospheric temperature as changes in the output of the sun. As humans cause the concentration of CO2 in the atmosphere to increase, even taking into account the absorption of CO2 by the ocean and vegetation plus the release of CO2 by the ocean, this has the same effect as an increase in sunlight caused by the sun.
Using variations in the Earth’s orbit, sunlight and ocean surface temperatures to explain changes in climate over time is like ignoring the effect of gravity on the orbits of the moon, earth and sun. Global climate varies over decades based on the laws of physics not variations in measurements of parameters like orbit, sunlight and ocean temperature.
Applying the basic laws of physics to calculating the average atmospheric temperature, as the concentration of CO2 increases in the atmosphere, means we can predict the future just like we can predict the tides. Denying the need to do anything now to deal with the certainty of a warming planet is like denying the need to move to higher ground before high tide.
By 2020, the earth’s average atmospheric temperature will have increased enough to cause a global migration and destabilize governments in developing countries. Some of these countries have nuclear weapons now or will develop them in the next ten years. We can not predict the consequences of this catastrophe only that it will happen.