The combined land and sea surface temperature is what most people think of first when they hear about global warming.
As at September 2016, August vied with July to be the hottest month in the instrumental record. Each of the last eleven months have been the hottest on record (hottest July, hottest June, hottest May etc.) The last two years have been the warmest years on record. The last decade is the fourth in a row to be the hottest decade on record.
Although it's not expected that every month or every year will be hotter than the one before (or the hottest ever), there has been a remarkable series of "hottest evers" recently.
Each of the past four decades has been hotter than any before it in the record. You can see this in the chart below:
The chart below shows the average of 12 months to August each year, ending with August 2016. The 12 months to August 2016 averaged 1.03 °C above the 1951-1980 mean and was 0.23 °C hotter than the 12 months to August 2015. Read more on the blog.
This next plot is the running average of the year to date as each year progresses. The first point on each chart is the average temperature for January of that year. The second point is the average of January and February, and so on. The final point on the years that have been completed is the average temperature for that year. For 2016, the last point is the average of all months to the last one plotted.
The troposphere is the layer of air immediately above the surface. There are two measures of the troposphere that are probably the most watched in regard to global warming, the lower troposphere and the troposphere. The two most commonly quoted sources of data are those maintained by remote measuring systems (RSS) and those maintained by the University of Alabama at Huntsville (UAH). Read more on the blog.
This chart is of the troposphere (RSS TTT). It shows the average 12 months to September, with the last data point being the 12 months ending September this year.
More than 90% of the extra heat we're causing is going into the oceans. Scientists monitor the changes in ocean heat through various means, one of which is the collection of Argo floats. These are free-drifting floats with instruments that measure things like temperature and salinity. They can sink to a depth of two kilometres (about 1 1/4 miles) and then slowly rise to the surface again, where they transmit data to satellites. These data are collected and analysed by scientists around the world.
You can read more about the Argo array, and details of how the floats are constructed and operate on the Argo pages.
This chart shows the change in heat of all the world's oceans combined since 1957. Since 1968, more than 30 x 1022 joules has been absorbed by the oceans. This is equivalent to more than 70,000,000,000,000 tonnes of TNT or 101,849,035,284,090,930 Big Macs - according to Alex Wellerstein. (That's the equivalent of more than 180,000,000 years of Big Macs sold in the USA.)