Measuring and forecasting global warming

The Goddard Institute for Space Studies, which is run by NASA, provides a wealth of global climate data on their site. I encourage you to check it out.

The site is continuously updated with global surface temperature data every month. They provide a wide range of maps and graphs that clearly show how much the Earth has warmed since the late 19th century.

Here are some of my favorite, most informative maps that are available...

The image above is very useful. The top part shows the long-term change in global temperature anomalies, but it also highlights when there was a major volcanic eruption. Large volcanic eruptions can cause a significant but short-term drop in global temperature due to the emissions of sun-reflecting aerosols high into the atmosphere.

The middle image shows the long-term difference in global temperature anomalies from land to ocean.

The bottom part tells you whether or not there was a El Nino (red) or La Nina (blue) event. El Nino tends to enhance warming, while La Nina has a cooling influence on global temperature.

This next image above is quite striking. It breaks down the global surface temperature anomalies by decade, which really shows the dramatic changes that we have seen, especially over the past few decades.

The final image below shows the plot of actual global surface temperature anomalies over the past 60+ years vs. a set of climate model predictions.

The actual temperature anomalies based on actual observations are shown by the black line. The colored lines show three different model forecast scenarios based on future greenhouse gas emissions. The green line assumes highest emissions, the blue is in the middle and the purple is the best-case scenario based on lowering emissions.

As you can see, we were tracking close to the lower emissions (better case) scenario early this century, but have unfortunately trended closer to the middle case scenario over the past five years.