[Source](https://www.sciencedirect.com/science/article/pii/S0277379119306924)
In a soon to be published paper found in the Quaternary Science Reviews, Volume 228, 15 January 2020, a study was made of tree-ring widths, over the past 5682 years. During this period, there were two warm periods coinciding with the Bronze Age Period (3140–2800BC) and Roman Warm Period (70BC – 150AD) which were warmer than our current period in the area of southern South America.
>Here we present a mean maximum summer temperature record, based on tree-ring widths, over the past 5682 years (3672BC – 2009AD) for southern South America (SSA), covering from mid-Holocene to the present...Our record explains 49% of the temperature variation, and documents two major warm periods between 3140–2800BC and 70BC – 150AD, which coincide with the lack of evidence of glacier advances in SSA. Recent decades in the reconstruction (1959–2009) show a warming trend that is not exceptional in the context of the last five millennia... a cooling trend has been reported along the Pacific coast (17° – 37° S) of South America for the periods 1979–2006 and 1981–2012 (Falvey and Garreaud, 2009; Hartmann et al., 2013).
[Source](https://www.sciencedirect.com/science/article/pii/S0277379119306924)
While in laboratories, CO2 can be demonstrated to have a major impact on the retention of temperature, in a real-world setting this can hardly be conclusive. People describe carbon dioxide as if it is a blanket that covers the entire world equally ignoring the point that in the areas of forest fires and volcanoes there would be much more and in other areas, it would be much less. Consider as an example that the difference between the Atlantic Ocean and the Pacific Ocean is roughly 20 centimetres.
Another aspect is the position of Earth relative to the sun. January 5th, 2020 the Earth will have the closest perihelion to the sun in our lifetimes. This coincides with the axial tilt putting the south part of Earth closer to the sun. It is unsurprising that Australia is currently experiencing forest fires. It is surprising but predictable that areas such as India are experiencing record cold while other areas (eg Chicago) are witnessing record warm temperatures. Solar forcing in one area will change the wind currents to others. It is amusing in an unfunny way that people in areas like India want to move to countries like Canada. "Extreme cold conditions continued in Delhi on Friday, December 27, as it witnessed a foggy morning with the mercury dipping to 4.2°C, two notches below the season's average." [Source](
https://www.oneindia.com/india/record-cold-spell-continues-in-delhi-night-temperature-to-fall-further-3004173.html) This time of the year, 4.2°C is considered unseasonally warm in Canada.
In addition to the CO2 and the sun, there are two many factors at play to simply describe what is happening. This following video describes another factor which is influencing our weather or will do so in the near future. It is one explanation of the 12068-year cycle from which we can anticipate wild and wonderful things from our closest star. Our two next closest neighbours have exhibited the results of this event.
https://youtu.be/ouGhtFOpaHM