b. Environmental observations are the foundation for understanding the climate system. From the bottom of the ocean to the surface of the Sun, instruments on weather stations, buoys, satellites, and other platforms collect climate data. To learn about past climates, scientists use natural records, such as tree rings, ice cores, and sedimentary layers. Historical observations, such as native knowledge and personal journals, also document past climate change.

This is a real-time map of current drought conditions in the US, which can be zoomed to the state level, with access to many more resources at that level. Some of these include the National Drought Regional Summaries and animations of historical data.

This video documents how scientists, using marine algae, can study climate change in the past to help understand potential effects of climate change in the future.

This video documents the scope of changes in the Arctic, focusing on the impacts of warming and climate change on the indigenous Inuit population.

In this activity, students explore how the timing of color change and leaf drop of New England's deciduous trees is changing.

The Greenland 2014: Follow the Water video is about Greenland's ice sheet, accompanied by computer models of the same, to show how the ice is melting, where the meltwater is going, and what it is doing both on the surface and beneath the ice.

In this 6-part activity, students learn about climate change during the Cenozoic and the abrupt changes at the Cretaceous/Paleogene boundary (65.5 million years ago), the Eocene/Oligocene boundary (33.9 million years ago), and the Paleocene/Eocene boundary (55.8 million years ago).

This video features scientists in New Zealand's Southern Alps, examining samples from the rocky landscape once dominated by glaciers. Their research, combined with other climate records, has revealed a link between glacial retreat and rising levels of carbon dioxide in the air.

This activity involves plotting and comparing monthly data on atmospheric C02 concentrations over two years, as recorded in Mauna Loa and the South Pole, and postulating reasons for differences in their seasonal patterns. Longer-term data is then examined for both sites to see if seasonal variations from one site to the other carry over into longer term trends.

Two graphs from the NASA Climate website illustrate the change in global surface temperature relative to 1951-1980 average temperatures. The NASA plot is annotated with temperature-impacting historic events, which nicely connect an otherwise challenging graphic to real-world events.

This color-coded map displays a progression of changing five-year average global surface temperatures anomalies from 1880 through 2010. The final frame represents global temperature anomalies averaged from 2006 to 2010. The temperature anomalies are computed relative to the base period 1951-1980.