Experts from The Environmental Protection Agency (EPA) discuss the drought surrounding the Panama Canal, its possible relation to global climate change, and its potential long-term impact on the ocean shipping industry.
Is there any conclusive impact of global warming on the current drought around the Panama Canal?
We are not aware of any specific analyses that have attributed a portion or likelihood of the current Panama Canal drought to climate change. Additionally, for a small region over a short time frame, there are many sources of variability that can contribute, such as El Nino.
How has climate change impacted the Central American region and, if there was any change, did emissions from the shipping industry’s vessels play a role?
Precipitation in that part of Central America is expected to decrease with warming. In addition to changes in precipitation, warming will also lead to increased evaporation. While the international shipping industry cannot be conclusively tied to the current drought, greenhouse gas emissions from the sector directly contribute to global warming.
Are there any models and/or charts that can highlight the areas of warming and changing precipitation patterns?
Yes. The climate models below illustrate how precipitation patterns will change around the world as the Earth warms. As you can see by the tan area around the Panama Canal, warming is expected to directly decrease precipitation levels in the region. The models also show that precipitation will decrease further as warming increases.
While we cannot conclude that the current drought is influenced by global warming, these models show that, over time, warming will significantly impact rainfall in that specific Panama Canal region. In addition to changes in precipitation, warming will also lead to increased evaporation.
How can climate change impact the global shipping industry?
Climate change can disrupt transportation networks, stress infrastructure, and even pose safety risks to those involved.
If the ocean shipping industry transitioned completely to alternative fuels like ammonia and LNG, would it have a positive impact on the environment, cutting greenhouse gas emissions, etc.?
Most ocean shipping vessels use diesel fuel as a fuel source to power the ship. By replacing the diesel fuel with ammonia, there would be considerably less CO2 during combustion as ammonia does not produce carbon. By replacing diesel fuel with LNG (methane), this would result in a lower carbon content than diesel, so a reduction in CO2 emissions is expected.
On the flipside of this coin, warming also causes increased precipitation in some regions and melting at the poles. How much would average water levels have to rise for port operations to be impacted?
Climate change is already impacting ports: every additional inch of sea level rise will increase the frequency and severity of those impacts. Global sea level rise is caused by heating of the oceans (“thermal expansion”) and by melting of glaciers and ice sheets on land. Local sea level is also impacted by land uplift or sinking (mostly caused by response to the melting of the ice sheets from the last ice age, but also augmented by groundwater extraction and other effects), changes in ocean currents, and even by gravitational shifts resulting from the melting of the ice sheets.
These changes have already led to increases in coastal nuisance flooding, particularly along the East and Gulf Coasts – see https://www.epa.gov/climate-indicators/climate-change-indicators-coastal-flooding. The National Climate Assessment (NCA) highlighted potential impacts to ports & harbors – “Ports, which serve as a gateway for 99% of U.S. overseas trade, are particularly vulnerable to climate impacts from extreme weather events associated with rising sea levels and tropical storm activity” and “Freight movement at major international ports can be delayed under extreme weather events that include heavy rains and/or high winds affecting crane operations and truck service” (https://nca2018.globalchange.gov/chapter/12/). The NCA did also mention the possibility for some positive impacts, namely “Milder winters will lengthen the shipping season in northern inland ports, including the Great Lakes and the Saint Lawrence Seaway”.