Climate change

First, climate change and the current episode of global warming is real and to claim otherwise is disingenuous. The peak of the last ice age occurred roughly 20,000 years ago, the peak of the next ice age is expected to occur about 80,000 years from now. Over the past 2,000+ years Earth has experienced multiple warming and cooling periods including the Roman Warm Period, the Dark Ages Cold Period, the Medieval Warm Period, the Little Ice Age, and the current warming period. Most (not all) of these variations in temperature can be explained by the amount of solar radiation reaching the Earth's surface.

Human activity is certainly responsible for some portion of the current warming, particularly through deforestation and urbanization. However many physicists who have a deep understanding of thermodynamics at the molecular level (NOT climatologists or meteorologists), argue that variation in solar radiation is the primary driver of climate change. Changes in incoming solar radiation can largely be explained by orbital cycles, sunspot activity, cloud cover, and volcanic eruptions. I think we can all agree that the amount of solar radiation reaching the Earth's surface plays a significant role in global temperatures and climate.

One factor often overlooked that influences the amount of solar radiation that reaches the earth's surface is cosmic rays. Cosmic rays ionize the atmosphere which provide condensation nuclei for water droplets to condense on. A decrease in cosmic rays results in fewer ions, reduced cloud formation, increased solar radiation reaching the surface, and warmer temperatures. Conversely, an increase in cosmic rays leads to more ionization, increased cloud cover, reduced solar radiation reaching the surface, and cooler temperatures. Cosmic rays originate both within and beyond our solar system and the number that reach Earth's atmosphere depends on several factors, main factor being the earth's magnetic field.

The only computer climate models that have come close to accurately reproducing past climate changes have relied primarily on factors that affect the amount of solar radiation reaching the earth's surface, NOT  greenhouse gases. CO₂ and other greenhouse gases (including water vapor which is by far the most abundant) have long been a theory of climate change but many physicists have proven otherwise.

Climate Change Theory (Douglas J Cotton, B.Sc (Physics))  http://www.climate-change-theory.com

Roy Spencer PhD https://www.drroyspencer.com

Article about solar variations based on Jupiter-Saturn and the 11-year solar cycle https://www.sciencedirect.com/science/article/abs/pii/S1364682612000648

 Article about how increased CO2 cools the atmosphere http://ruby.fgcu.edu/courses/twimberley/EnviroPhilo/CoolingOfAtmosphere.pdf

Astronomically based decadal-scale empirical harmonic climate model http://www.sciencedirect.com/science/article/pii/S1364682611003385

Global temperature report of the lower troposphere https://www.nsstc.uah.edu/climate

That's 0.3% consensus, not 97%! https://joannenova.com.au/2013/07/thats-a-0-3-consensus-not-97

Consensus among scientists crumbles (Forbes)  http://www.forbes.com/sites/jamestaylor/2013/02/20/as-the-consensus-among-scientists-crumbles-global-warming-alarmists-attack-their-integrity

Documentary "The Great Global Warming Swindle". https://youtu.be/H3IhIUBghPc

Data from https://www.nsstc.uah.edu/climate

Average of 18 non tree ring proxies of temperature from 12 locations around the northern hemisphere published by Craig Loehle in 2007.

General chart of the effect of sunspot activity & Milankovitch orbital cycles have on the earths temps.

Interglacial Temperature over the last 10,000 years.

Global mean temp over the last 500,000 years, snowflakes mark the peaks of the ice ages.

In the past CO2 increases lag behind global temperature increases by about 800 yrs.