Originally Posted by
73qanda
This is where it gets hairy Dre. You say it’s scientific fact and mention that you have already explained that to us.....
It’s hard to see how the climate model predictions are ‘scientific fact’.
Just to make sure we are not misunderstanding each other, can you answer the following statement with a true or false, it would help my understanding of your position as the discussion continues.
’ Climate Model predictions of future global temperatures are scientific fact’ TRUE/FALSE
"Predictions of future global temperatures are scientific fact - FALSE" (I'm not dr dre, but thanks for your continued efforts dr dre!)
They are predictions, but based on observations. Observations are scientific facts, for example the observations by NOAA that 2016, 2015, 2017 and 2018 were globally the four hottest years in the modern temperature record ( last 139 or so years of accurate direct global measurements). Even if you decide that you want to restrict your era of measurement solely to the timeframe when satellites could measure global temperatures in the last 4 or 5 decades, they're still the 4 hottest years in the recent record. Predictions were made years ago, decades ago, that increasing the carbon dioxide levels in the atmosphere would lead to a greenhouse effect creating an overall warmer planet, and we have continued to increase the CO2 levels, and observed a warming planet roughly in line with the predictions. Theyre not a perfect prediction, and have ranges of probable outcomes, but generally the results observed globally have been in line with what was expected.
How do we know that CO2 is involved? Effectively there's only two very broad ways the planet warms, either by having more solar radiation fall on it due to variations in solar orbit or activity, or by retaining more of the heat that is incident on it. All the historical ice ages and warm periods can be attributed to one of those things, or their effects combined. The planet's orbit is slightly elliptical, but this would result in annual cycles, not the observed decade-scale warming trend.. Similarly, solar activity follows cycles, but this cyclical variation in output is not reflected in the warming that has been observed - not that it isn't present, but the observed warming trend is beyond that cyclical variation, and at times in contradiction to what would be expected if planetary temperature changes were primarily driven by solar (sunspot) activity. The levels of solar radiation falling on the earth are not changing (increasing) rapidly enough to create the observed trend. Those are some scientific facts, based on observations, they dont predict anything in the future at all.
So something is happening to cause the earth to retain more heat. Basic repeatable physics experiments that any science lab or dedicated backyard experimenter can reproduce show that CO2 has a greenhouse effect, and predictions were made in previous decades that an increase in CO2 levels would lead to a warmer planet, which has been borne out by recent observations. Existing climate models predicted the observed warming trend years before it was seen, which gives them some validity. Based on that, with models that predicted changes that were later observed, a large number of climate scientists are predicting due to those models that a further increase in CO2 levels will lead to further warming.