PrintThe impacts of climate change on cities and the coastal zone will be significant and are compounded by the fact that coasts double as population centers for almost half of the world's people.This growing density of population in the coastal zone is exposing more people and infrastructure to climate change, greatly intensifying the impacts.
Coasts
Ocean warming, sea level rise, and ocean acidification are clearly observable today and their impacts are unavoidable. Even with strong, concerted efforts to mitigate climate change, and even if the polar ice sheets do not collapse and cause catastrophic sea level rise, ocean warming and sea level rise will accelerate during the 21st century because of the climate system’s inherent lags and the thermal inertia of the ocean. Sea level rise will continue for centuries, again because of the ocean’s thermal inertia. Ocean acidification mirrors carbon emissions to the atmosphere, so the oceans will continue to acidify for as long as carbon emissions rise, but will fall when emissions eventually fall. In this lesson, you also learned that cities are already feeling the impacts of climate change, but that those impacts are going to get much worse as cities continue to grow and as climate change continues to intensify. You found out that the human systems most affected by climate change are utilities and infrastructure, industry, services, and social systems. You discovered that the overall vulnerability of any city is a function of its location, size, and type of economy. Finally, you learned that although the capacity for adaptation is generally high in cities, four factors complicate adaptation: adaptation depends on the rate and magnitude of climate change; adaptation links to economic, political, technical, and social systems at scales ranging from local to global; climate change is only one of many risks that cities manage; and adaptation sometimes has unanticipated consequences.
In short, the impacts of climate change on the coastal zone will be momentous. Significant coastal adaptation is unavoidable and will be costly. To minimize these impacts and costs, climate change mitigation is critical and should start at once. In this lesson, you learned about the physical impacts of climate change on coastal zones, especially sea level rise and the two factors –– glacier melt and thermal expansion of sea water –– driving that rise. You read that sea level rise causes many problems such as coastal erosion, enhanced storm surge, and salt water intrusion. You also learned that climate change melts coastal permafrost, kills corals, and acidifies seas. These and other physical impacts have tremendous impacts on humans and the built environment, which are best understood by examining vulnerability's three dimensions: exposure, sensitivity, and adaptive capacity. The lesson compared the costs of adaptation to the costs of failing to adapt. It concluded that the impacts of climate change are unavoidable in the coastal zone, so adaptation should start at once.
Cities
In this lesson, you have learned that cities are already feeling the impacts of climate change, but that those impacts are going to get much worse as cities continue to grow and as climate change continues to intensify. You found out that the human systems most affected by climate change are utilities and infrastructure, industry, services, and social systems. You discovered that the overall vulnerability of any city is a function of its location, size, and type of economy. Finally, you learned that although the capacity for adaptation is generally high in cities, four factors complicate adaptation: adaptation depends on the rate and magnitude of climate change; adaptation links to economic, political, technical, and social systems at scales ranging from local to global; climate change is only one of many risks that cities manage; and adaptation sometimes has unanticipated consequences.
Coastal Cities
We've explored the challenges coastal environments - both build and natural - face in a changing climate. We've also learned about the challenges for cities. When we tie these challenges together and look at the compounded dangers for coastal cities, the urgency of the problem emerges. With so much of the world's population relying on coastal cities for their homes, livelihoods, and global economy, there is much to be lost to adverse impacts from climate change.
Extreme Weather
Obviously not all extreme weather risk happens at the coasts or within cities, but we've explored them together, recognizing that when these factors overlap - coastal cities experiencing extreme weather events - the climate impacts for people and our environment are high. While the connections between some weather events and climate change are not as clearly understood as others, people are increasingly vulnerable to these events as they become more severe and frequent. We'll spend some time in Unit 3 talking about how we can respond to these events to increase our adaptive capacity.
Reminder - Complete all of the Lesson 5 tasks!
You have reached the end of Lesson 5! Double-check the lesson assignments in the corresponding lesson module in Canvas to make sure you have completed all of the tasks listed there.