The International Panel on Climate Change (IPCC) has concluded that warming of the climate system is unequivocal. Temperature of the ocean and CO2 concentrations are key parameters in the Earth’s changing climate. The Agency has developed tools that use radionuclides and isotopes to track climate change. Radionuclides such as radiocarbon, 230Th/234, and Pb-210 are used to date marine records such as corals and sediments, which are helpful to reconstruct past climate. For example, in the framework of the CRP on Nuclear and Isotopic Studies of the El Niño Phenomenon in the Ocean, nuclear techniques are used for studying the isotopic composition of seawater and corals in the Pacific Ocean with the aim of deriving past environmental records in the oceans. Further elemental and isotopic analysis reveal temperature records going back several hundreds of years.
Climate records can be obtained from a variety of environmental archives such as sediments, corals, sponges, tree rings and speleothems. These are also used to reconstruct ecosystem health in the past through indicators such as sediment accumulation, lipid biomarkers and pollution level trends.