Of the hottest years on record, 15 out of 17 have come since 2000. By contrast, more than a century has gone by since the planet had a record cold year (1911). In addition, this marks 39 years in a row with above average global temperatures and 372 months in a row with global temperatures above average.
Source:
http://www.climatecentral.org/gallery/graphics/the-10-hottest-years-on-recordOK, so this data seems compelling, especially when we take into account the correlation between the increase in temperature and the increase in CO2 in the atmosphere:
Source:
http://climate.nasa.gov/climate_resources/24/I understand that the Earth's temperature has fluctuated
a lot more in the past than it is now, but never with the same correlation of CO2 concentration in the atmosphere.
I also understand that the concentration of CO2 has often lagged behind the temperature changes in the past, but as I understand it this is a two way street - if the CO2 concentration gets too high, too quickly, it can certainly cause warming and a feedback loop. Just because this hasn't happened in the past doesn't mean it isn't happening now.
Not to mention there could be other effects of such a rapid warming, such as methane being released from permafrost, causing the feedback loop to become even more extreme.
Another interesting link regarding the authorities/groups of scientists that are actually measuring the changes in temperature - It seems that there are 4 independent bodies producing datasets in this field:
https://www.carbonbrief.org/explainer-how-do-scientists-measure-global-temperatureAlthough not a huge amount of datasets, their data seems to correlate reasonably closely as far as I can see, and it's certainly not a single organisation making up data as they go along.
Yes, many of the earlier climate models that people shouted about 5-20 years ago were way off, but that doesn't mean that the current data is wrong. Past performance is not necessarily an indication of future performance - you just need to look at the Bitcoin charts to see that!