To what degree does historical measurement inaccuracies contribute to climate change models? Often the graphs depicting the earth's historical temperature, the time axis extends well over couple of centuries. Also there are few that extends over thousands of years.
I wonder to what degree the measurement inaccuracies are taken into account while using these charts to communicate the ongoing climate change. Its a valid question that older temperature measurement suffer a higher error compared to modern day's methods.
Even the feared 2.5°C temperature rise over the industrial revolution time is a minute variation over centuries. To what degree has the climate models taken into account these measurement errors into account? (In short, the question is basically from a climate change sceptic that goes like - &quot;Thermometers have gotten better and we are just measuring the true temperature and it's not that the world is warming up. So how can we accept climate change/global warming?&quot;)
I would estimate 0%, as long as we are considering the same types of models. See, climate models and in the regard that you may think of observations. Climate models aren't really initialized on observations of the system, but rather on inputs/forcings and mean state.
Observations of today's climate may validate the accuracy/tuneness of a climate model, but the types of observations used to run climate models may be different from what you expect. For example, the thermometer was invented either near 10 AD or in the 17th century, so it was obviously not a widespread invention then. Usually, those temperature measurements are taken as proxies, such as the amount of oxygen isotope or atmospheric composition in ice cores. So the answer to the climate skeptic is that it isn't just the temperature itself, but the modern day observations of temperature proxies that show past warming.