I mean, have any Pacific Ocean species invaded the Caribbean, or the opposite? I know that ships must travel through fresh water, which should kill anything hitching a ride. But, in 100 years, has anyone noticed any bad effects?
That article is terrible. I don’t see any citations of the primary peer-reviewed literature. Most of the citations are of newspaper or magazine articles, Wikipedia, secondary sources such as books for a general audience, etc.
In terms of the preservation and protection of tropical forests, the Panama Canal was a net positive. Far from being cut through unbroken forest, the Panama Canal route followed the main route of transit across the isthmus that already had been the site of Spanish colonial trails and the Panama Railroad. This region had already been mainly deforested for at least 400 years (and probably longer, since there had been dense settlement in the area in Pre-Columbian times). Very little old-growth forest remained.
When the Canal Zone was created, most of the previous residents were moved out, and subsistence agriculture and cattle raising were terminated. The forests of the area mostly regenerated, and the area is today covered covered with tall forest (although mostly less than 100 years old.) In the meantime, areas outside the Canal Zone in Panama were almost entirely deforested for agriculture and cattle, especially after the 1950s.
Fortunately, once the Canal Zone reverted to Panama, Panama decided to protect most of the forest areas in the area as National Parks and other reserves. Today what I call the “ghost of the Canal Zone” can be seen as 10-mile wide strip of forest, surrounded by deforested land, that runs across the isthmus within the boundaries of the former zone.
The need for water to operate the locks of the Canal has also prompted conservation of forests in the headwaters regions of the Canal Watershed, including Chagres and Altos de Campana National Parks.
With regard to oceanic species, most salt-water species are prevented from crossing between the oceans by freshwater Lake Gatun that forms the central part of the Canal. A few species have made it across, but I am not aware of any serious environmental problems they have caused. However, it suspected that a disease that decimated a species of sea urchin in the Caribbean about 30 years ago may have crossed from the Pacific via the Canal.
There are lots of invasive marine species that have arrived in Panama, but they have mostly come in ballast water of ships arriving at either entrance of the Canal. They have colonized areas near the Canal entrances on each coast, but have (mostly) not crossed the isthmus.
If you consider all of the fossil fuels that have been transported through the canal and the eventual impact on climate change they have had, it would be considered catastrophic.
Well that’s the same argument they are making against the XL pipeline.
Moderator Note
Let’s not get off on a tangent about the XL Pipeline. This is about the Panama Canal.
Colibri
General Questions Moderator
Looking forward to a trip through later this fall. Kind of a “bucket list” thing.
The canal is not a sea level man-made strait: it’s a series of locks that raise and lower ships over the spine of the isthmus, using the fresh water mentioned upthread. One reason a sea-level canal has never been constructed is precisely because of the concern over invasive species.
An extremely minor reason. There’s a mountain range between the two oceans; moving all that rock is expensive and probably logistically impossible.
You believe that without the Panama Canal, these would not have been transported?
(Also, FWIW, fossil fuels are mostly moved by ships too large for the current Panama Canal.)
Not saying my post was meaning I was going to cause an ecological disaster, by the way. 
Hey Colibri! That photo link didn’t load for me.
Two other unintentional and very successful wildlife preserves are the Korean DMZ and Chernobyl.
Works fine for me. I’m not sure what the problem is.
Im as much an environmentalist as the next guy, but it seems to me the environmental impacts are localized while the benefit to the world economy and to the climate in terms of fossil fuels being released into the atmosphere and danger to life and property going around Cape Horn make this project well worth it. The idea of sending ships around the tip of southern Chile or South Africa to me would have been ridiculous concepts in the 20th century.
Actually, the amount of oil transported through the Panama Canal is quite trivial compared to other marine routes. And as you point out, by allowing ships to use much less fuel than going around Cape Horn it is surely a net benefit in terms of the global carbon budget.
Also because modern tankers (supertankers) for decades have been far too big for the canal. Plus, since much of the world’s shipped oil comes from the middle east, there are direct routes to the Atlantic and Pacific.
Thanks for the replies. i always wondered-with modern containerized cargo handling machines, does the canal make sense? You could off load on the Pacific side, ship the containers via rail, and reload on the Caribbean side-using no water and very little energy. Of course, it would increase the idle time of ships that would have transited-but would offloading/reloading make sense?
That depends on what you’re asking. If we were to build the canal today, would it make sense versus railing the cargo containers? Maybe not. But given that we do have the canal, and don’t have the rail infrastructure, does it make sense to keep using the canal? Probably.
And while a sea-level canal was basically impossible across Panama, wasn’t there another proposed site in Nicaragua that would have been much closer to sea level?
The Nicaragua canal proposal looks like it is viable, but given the Chinese stock market, unlikely.
There is a railroad paralleling the Panama canal. And good-sized container ports on both ends of the canal mouth doing exactly that sort of transshipment.
Although the railroad itself dates back to the early days, the vast majority of this transshipment volume has been developed since I lived there in the 80s. The port infrastructure and the railroad capacity have expanded 10-15x since then.
The big driver has been the growth in the size of container ships. In the early days of containers the ships fit through the canal. Now they don’t.
The other driver is that global shipping traffic has also increased a bunch since the early days. In my era it was not uncommon for an arriving freighter to wait 2 days for its turn to transit the canal. Which took several hours. With today’s volume, the wait is even longer.
So if we can dock the ship, offload it, railroad the containers to the other side, and reload another ship faster than the time to wait + sail the canal, it becomes more efficient overall to do so.
The new and improved canal which can accommodate more and much larger ships will alter the balance between canal transits and portage-cargo-via-rail transits. But it won’t eliminate the need or desire for the rail system.
Yeah, well, of course it works now. 
It’s too late! I wanted to see it yesterday! :mad: