Fixed that for you.
Facts:
What is occurring is not natural climatic variability. The periods of glaciation and warming over the last 3.5 million years (24 so far) are explained by variations in the Earth's orbit (The Milankovitch Cycles). The Earth's orbit moves closer to the sun, the Earth surface receives more solar energy, it warms up. It moves away, less solar energy it cools down. In the geological scale of time, we're due for another ice age: the earth's orbit is not getting closer to the sun. So that isn't causing the warming that most honest scientists see.
Also note that during those earlier interglacial periods, the concentration of CO2 in the atmosphere never exceeded 300ppm. It is close to 400ppm now and will likely hit 600ppm within a few decades. Please do not try and say that CO2 does not have a greenhouse effect because this is basic physics understood by all scientists for several hundred years. It is fact that is not in question by any knowledgeable person.
If we look at the Holocene Climatic Optimum (5,000 to 9,000 BCE), the name for a time period that the Aussie says no one uses any more, the climate was warmer and wetter on the Eurasian continent with 2-3 degrees warming in the Arctic and Northern Europe, but almost no warming in the tropics and cooling or no change in the southern hemisphere. A local climatic zone. The Holocene Climatic Optimum is predicted by the Milankovitch Cycles with the earth's axial tilt at 24 degrees at the time, its steepest value (currently it is 23.4 degrees). The northern Hemisphere was more exposed and received more solar energy while the southern hemisphere was less exposed and received less energy.
We know that the medieval warm period (about 950 to 1250 AD) was a localized weather condition in the northern hemisphere which saw about a 1 degree higher average temperature. Globally, the south was cooler and the average global temperature (the issue at hand) fell a bit, about 1 degree, during this "warm period". The current heating we are seeing is global in reach and warms both poles. So it is different from what occurred in these two previous events that the Aussie spoke of.
So lets blame volcanoes, methane or increased solar activity. Nope. Solar output has been dropping since 1940 so we should have been seeing cooling. but it's been warming instead. Methane. Methane is a more powerful greenhouse gas than CO2, but there is 200 times as much CO2 in the atmosphere as methane, so CO2 is the gas that provides the majority of the greenhouse effect of the gasses in our atmosphere. Volcanoes. Volcanoes are the cause of the nasty greenhouse gasses that cause the warming. Nope. Volcanoes erupt the staggering amount of about 300 million tonnes of CO2 into the atmosphere each year. Human activities on the other hand emit only 29 billion tonnes per year, just 100 times what volcanoes put out.
The climate records show cooling / flat since 1998. Of course 1998 was a record El Nino year so in relation to that extra warm year caused by a known oceanographic condition, 1999 & 2000 look cool. They still fall in the top 20 hottest years ever recorded.
So we know that changes to solar output is not causing the warming that is happening. We know that orbital dynamics are not causing the warming that is happening. We know that Volcanic activities and methane gas emissions are not a major cause of the warming that is happening.
