365 Days of Climate Awareness 89 - 2019 IPCC Special Report on the Ocean and Cryosphere

Between releases of major assessment reports (most recently AR5, 2013-14, and AR6 2021-22), the Intergovernmental Panel on Climate Change releases Special Reports on more narrow topics, which contain up-to-date scientific information and serve as preparation for the next upcoming Assessment Report. With the first volume of AR6, The Physical Science Basis, being available for now only in draft form, it makes sense to look back to one of the earlier special reports which contributed to it. The upcoming series of posts draws information from the 2019 Special Report on Ocean and the Cryosphere.

Liquid, solid and gaseous phases of water on earth are a closed thermodynamic system, gaining and losing energy but not mass, as water moves between all three phases above, on, and within the planet. Monitoring changes in mass balance between the three, and changes in condition of each, is a challenging but effective way of tracking climate change.  

The illustration shows how these trends accompany each other. Causative links between them have been established, and one of the main tasks now facing researchers is using recent data to continue refining the climate models which describe the changes we observe, in order to better predict the future.

Rising global temperatures generally raises the ambient temperature in the atmosphere and the ocean, and shifts the balance of mass toward higher energy states: from solid to liquid, and from liquid to vapor. The CO₂ mostly responsible for this temperature increase leads to greater acidity (lower pH) in the seawater. Increased temperatures in the atmosphere and ocean lead to increasingly stratified layers of water, which results in lower oxygen levels deeper in the ocean. No trend exists in isolation. The system is moving as a whole.

Tomorrow: some specific temperature trends of the past century.

Be brave, and be well.