A few things to bear in mind, race is far more of a cultural construct than a genetic one. Compared to other species we don't show much genetic variation, and people of African descent are much more genetically diverse than the rest of humanity. Another is that IQs have been rising steadily around the world, proof that environmental factors such as nutrition and education have a a large effect.
The Bell Curve has been thoroughly debunked I believe. Genetics aren't nearly as important as environment for IQ scores, as proven by adopted children.
On the other side of the world, we had record temperatures across Europe as well this year. Fewer deaths than the 2003 heatwave though as people were generally better informed of the risks.
> ...you'll see that temperatures swung as much as 8C during the ice age. The last glacial period itself covers some 100,000 years.
I could have phrased it better, I'm talking about the temperature difference between the end of the last age and the current day.
> ...Dansgaard-Oeschger events
The recorded temperature swings are local rather than global, global temperature does not rise by five degrees in a matter of decades unless something catastrophic happens.
> There's thousands of papers on the Little Ice Age. It certainly shows up all over the world in the fossil record.
Yes, but average global temperatures were barely affected.
Historical civilisations were very vulnerable to changes in local climate as they were heavily reliant on local food production, whereas we routinely ship food across oceans. Events like the [Little Ice Age](https://en.wikipedia.org/wiki/Little_Ice_Age) barely show up in the global climate record.
Earth's climate has varied greatly over time but its the current rate of change that is so alarming. During the last ice age it was about 4.5 degrees colder but it took 10,000 years to reach modern temperatures. We're currently on a path to changes of that magnitude within the next 70-100 years.
All informed decision making is made on the basis of probabilities. You're setting an impossibly and arbitrarily high threshold for action on climate change.
The burden of proof is on you to explain how CO2 levels not seen for 3 million years won't have a major impact on the biosphere.
Modelling has its limitations but those are well understood by the people building the models, which is why they predict a range of outcomes and uncertainty rises with time. Most of the uncertainty in current models has to do with the complexities of cloud formation.
We've had usefully predictive models for over 50 years now. The first real paper model from 1967 successfully predicted warming up to the current day.
Certainly not within 50 years, but this is based on projected wet-bulb temperatures around the equator. The limit for human survivability is the equivalent of 35C at 100% humidity.
"A sustained wet-bulb temperature exceeding 35 °C (95 °F) is likely to be fatal even to fit and healthy people, unclothed in the shade next to a fan; at this temperature our bodies switch from shedding heat to the environment, to gaining heat from it. Thus 35 °C (95 °F) is the threshold beyond which the body is no longer able to adequately cool itself. A study by NOAA from 2013 concluded that heat stress will reduce labor capacity considerably under current emissions scenarios.
A 2010 study concluded that under a worst-case scenario for global warming with temperatures 12 °C (22 °F) higher than 2007, the wet-bulb temperature limit for humans could be exceeded around much of the world in future centuries. A 2015 study concluded that parts of the globe could become uninhabitable. An example of the threshold at which the human body is no longer able to cool itself and begins to overheat is a humidity level of 50% and a high heat of 46 °C (115 °F), as this would indicate a wet-bulb temperature of 35 °C (95 °F)."
Our window to escape this future in narrowing. Here in the UK 3 years of Brexit arguments have sucked up all the oxygen. While on the other side of the Atlantic a science denier is squatting in the White House.
> Lastly, what's even the big issue with changes in global temperatures? Even without humans, this planet would go in and out of ice ages on semi-regular intervals. We can't really control that. Life adapts.
The issue is the rate of change, which is unprecedented. The path we're currently on will devastate ecosystems and cause a huge drop in crop production.