geography final worksheet

Atmospheric CO2 concentrations

§ Ice cores extend atmospheric CO2 records further back in time.

§ Atmospheric CO2 concentrations increase with the onset of the industrial revolution.

§ Present atmospheric CO2 levels are the highest within the past 800,000 years.

We know from previous lectures that we only have atmospheric CO2 concentration measurements since 1950s. That being said, we can extend our atmospheric CO2 records using ice core data.

Temperature and CO2 • Increasing CO2

concentrations are associated with increasing temperature.

• With our current high levels of atmospheric CO2, there is much interest in knowing what conditions on Earth will be like in the future.

• To predict future conditions, knowledge of natural climate variability is essential.

Changes in Global Sea Level

Global sea level gradually rose in the 20th century and is currently rising at an increased rate, after a period of little change between 0-1900 AD.

When temperatures rise due to increases in greenhouse gas concentrations, global sea levels rise due to thermal expansion of the water body by added water from melting ice, and other miscellaneous reasons.

Further reading: https://www.climate.gov/news-features/understanding-climate/climate- change-global-sea-level

Allison et al. (2009) http://www.copenhagendiagnosis.com

This figure shows sea level change during the period between 1970-2010. The red line shows tide gauge data (Church and White 2006) and the blue line is satellite observations (Cazenave et al. 2008). The grey band shows the possible future projections based on the IPCC Third Assessment report published in 2001.

From this figure, it is clear that the actual observed measurements based on satellite imaging confirm the highest margin of sea level change that climate model projections made for the IPCC Third Assessment report. In fact, climate models underestimated the rate of sea level rise. This is because the rapid melting of the ice sheets and glaciers were not incorporated in the Third IPCC report. At the point of publication, the melting of the ice sheets and glaciers were not included because this data were considered insufficient at that time.

Water Vapor

Lapse rate

Clouds

Cryosphere

NASA VIDEO

https://www.nasa.gov/press/2014/september/2014-arctic-sea-ice-minimum-sixth-lowest-on-record/

Please visit the following link to watch a video clip from NASA’s website, and give some thought to how much water has been added due to melting of Arctic sea ice.

https://www.nasa.gov/press/2014/september/2014-arctic-sea-ice- minimum-sixth-lowest-on-record/

Observed sea level since the start of the satellite altimeter record in 1993 (black line),

plus independent estimates of the different contributions to sea level rise: thermal

expansion (red) and added water, mostly due to glacier melt (blue). Added together

(purple line), these separate estimates match the observed sea level very well.

NOAA Climate.gov graphic, adapted from Figure 3.15a in State of the Climate in 2018.

https://www.climate.gov/news-features/understanding-climate/climate-change-global-sea-level

This is an updated figure showing the observed global sea level change between 1993 and 2018. Please note what is contributing to such increases in sea level. Currently, approximately 30% is caused by thermal expansion, which occurs due to warming of the ocean water, and almost two thirds of the global sea level rise is due to increasing volume of water, mostly from melting glaciers.

Climate Sensitivity

Climate Sensitivity As we learned earlier this semester, climate sensitivity is formulated by

this simple equation.

ΔTs= λ*ΔF

λ = Climate Sensitivity (°C/Wm2) T=Temperature at equilibrium ΔF= change in forcing (W/m2)

Kalkar, Germany

In order to change a climate forcing, we need to change the rate of greenhouse gas emissions. Here is an iconic and powerful example from Germany.

What do you think this amusement park made of?

(Please see following slide.)

A nuclear reactor at Kalkar was finished just before the 1986 explosion at Chernobyl, Ukraine—and never used. It’s now an amusement park with a ride in what would have been the cooling tower. Fear of nuclear power spurred Germany’s transition.

This example should provide us with hope and a message for our future. Can we transfer our energy production into a safer and less expensive source of alternative energy? And how soon?

We will continue this discussion and develop a deeper understanding of these issues.