Lecture 18

• human population has increased massively
• anthropogenic carbon input creates an imbalance in the global carbon cycle
• the increase in atmospheric CO2 concentrations is directly linked to increasing temperatures
• 23 January 2023 a huge iceberg (1550 km^2), almost the size of greater London has broken off the 150 m thick Brunt Ice Shelf
• major melting will result in sea level rise
• sea ice melting is a feedback loop as there is less ice so there is less albedo effect
• effects of warmer ocean temperatures:

  • fish species are pushed towards cooler latitudes and out of reach of artisanal fishers
  • coral bleaching across the tropical belt (most reefs enter a state of permanent decline by 2040)
  • the rate at which water absorbs CO2 decreases as water temperature increases
• the decrease in the pH of the oceans is caused by the CO2 uptake from the atmosphere. Seawater is slightly basic (meaning pH>7), and ocean acidification involves a shift towards pH-neutral
• on land, a warmer climate coincides with higher fire risk
• increasing temperatures are also making the world's water woes more urgent
• the worlds water resources are mainly in salt water and we use fresh water sources heavily
• global warming is not uniform