Computer models looking into future climates need to be tested using data from the warm climates of the past. If the models can accurately reproduce past warm climates, we can be more confident in their predictions of future greenhouse climate.
The Museum has been helping the Tanzania Drilling Project led by Cardiff University to sample mud laid down on an ancient seafloor. The mud layers are about 55 to 35 million years old, recording a past greenhouse climate when the Earth had no ice caps. The fossils of tiny single-celled animals called foraminifera are used to date the layers, and their chemistry is used to track climate change through time.
The Tanzanian sediments are special because they have excellently preserved fossils. The mud is rich in impermeable clay, so modern rainwater has been prevented from dissolving the fossils and resetting their chemistry. Equally, the mud was laid down at a high rate. A large thickness represents a short time interval, so changes through time can be seen in great detail.