# 9.1: Background


The Climate Dashboard is a collection of interactive graphs looking at six major climatic elements over the past millennia. These include global temperature, mean sea level, and oxygen ($$O_{2}$$), methane ($$CH_{4}$$), nitrous oxide ($$N_{2}O$$), and carbon dioxide ($$CO_{2}$$) levels. Each of the graphs allows you to zoom in enabling you to look at it more closely and zoom out showing changes back through several major ice ages – the last 800 thousand years.

The temperature graph on the dashboard shows the difference between the global average annual temperature for any one year and the global average for the 1850s, often regarded as the start of the industrial revolution. This difference is referred to as a temperature anomaly and is displayed for the past millennia on the default graph. The graph can be expanded to show temperature variation over the past 800,000 years.

The other environmental factor shown in the dashboard is global mean sea level. Since we will only be dealing with the temperature graph in this activity set, an explanation of what mean sea level is, how it is measured, and its impacts will appear in a later activity in this manual, Activity 16, Sea Level and Coastal Flooding.

The other graphs on the dashboard show levels of major atmospheric gasses. Though we won’t be dealing with these, either, in this activity set, here is a bit of useful background.

Of the four gasses shown on the dashboard, one of these, oxygen, is a major constituent of atmosphere. At sea level, the atmosphere is approximately 78% nitrogen and 21% oxygen. The remaining 1% of the atmosphere is a combination of gasses that occur in such small concentrations that they are referred to as trace gasses.

Three of these gasses ($$CO_{2}$$, $$CH_{4}$$, and $$N_{2}O$$) that appear in the dashboard are also Greenhouse Gasses. Their significance is explained in two earlier activity sets, Activity 4: Atmospheric Energy Budget and Activity 5: Carbon Cycle.

9.1: Background is shared under a CC BY-NC license and was authored, remixed, and/or curated by Frank Granshaw.