News from a Changing Planet -- #4
(For all those who want to hear about developments in the world of climate research…this is for you!)
Too cool to lose!
Coral reef bleaching is an effect of climate change that even someone who doesn’t pay all that much attention to climate change and environmental news (not you, of course!) might know about.
Most corals play host to photosynthetic algae living in their tissue. These algae (zooxanthellae) provide nutrients to the coral, allowing them to grow and thrive! They also give corals their color. When corals get stressed (for instance, if the water is too warm), they spit out the zooxanthellae, losing their color and turning white, which is why this process is called coral “bleaching.” If the coral goes too long without zooxanthellae, it dies.
We’ve seen mass die-offs in the Great Barrier Reef and elsewhere around the world, which are caused by warming ocean temperatures brought by climate change, and can sometimes be attributed to extreme events like El Niño. But warming sea surface temperatures are not the only stressors facing coral reefs, which brings me to this week’s news: a new study in Marine Biology that explains why Florida’s coral reefs are dying too.
This study looked at waters around the Florida Keys over a period of 30 years, and found that nitrogen pollution from sewage and agricultural runoff is also responsible for mass coral deaths.
Florida Bay and part of the Florida Keys National Marine Sanctuary
In Florida, the researchers were able to link the nitrogen pollution to increased sewage pollution, a result of the boom in tourism and development in the Florida Keys, and agricultural and industrial runoff, likely from the Everglades. (To find out more about nutrient pollution, just wait for my book! Or read more here.)
This is how run-off gets into our water!
The Everglades part is what’s especially interesting to me, for a few reasons.
1. Florida Bay also has very high levels of salinity, and so environmental agencies and policymakers decided to increase the amount of freshwater runoff from the Everglades into the ocean to make it less salty. The water gets less salty when they do this, but because this water contains nitrogen from agricultural and industrial operations upstream of the Everglades, the process also has led to significant algal blooms, growth of cyanobacteria, and eventually coral reef death. It's an ongoing problem!
The Everglades
2. Climate change will make nutrient pollution worse, by increasing the frequency and strength of extreme precipitation events, causing more fertilizer and pollutant run-off, and, by extension, more nutrient pollution.
Nutrient pollution on the St. Lucie River, which feeds into Florida Bay.
3. Population growth also probably won’t help matters: more waste, more sewage, more fertilizer to grow more food, if we don’t change things.
So why did I write about this study?
Primarily, this whole thing tells us that all environmental issues are now climate issues, and climate change issues can’t be separated from longstanding environmental issues like pollution, either. Warming alone doesn’t cause coral reef bleaching, and identifying other causes doesn’t mean we can forget about warming. These problems are local (nutrient pollution) and global (rising sea surface temperatures) at the same time, and we have to look at solutions that way too.
Better wastewater treatment plants will help prevent pollution from sewage.
Fertilizer is responsible for 1-2 percent of global greenhouse gas emissions, and most nitrogen pollution is caused by fertilizer run-off. Using less fertilizer would reduce the amount of warming emissions, and it would also have dramatic implications for soil health and water quality. Healthier soil means less fertilizer, which means cleaner water; healthier soil also stores more carbon, which is one of the best ways to reduce emissions from the agricultural sector.
Which brings me to the 2020 election (surprise twist!). Democratic candidates for president have been talking a lot about climate change, and focusing particularly on rural/agricultural solutions in Iowa of all places!!!!! I wonder why!!! Just kidding - I know why and it's also why we still have ethanol subsidies.
Earlier this week, Joe Biden released a policy proposal for rural America that includes a goal of an agricultural sector with net-zero emissions. His plan relies heavily on paying farmers to store carbon in their soil, through practices like planting cover crops. (This program already exists but often runs out of money, and the Trump administration wants to get rid of it.)
The problem: Biden’s plan is voluntary, as is the current plan. So far, voluntary efforts to get farmers to “store carbon” in their soil or reduce their fertilizer use have not been very effective.
Algal blooms in Lake Erie in 2017, a result of agricultural runoff in the Corn Belt. In this case, phosphorus is causing the algae to grow since it's in fresh water.
Senator Michael Bennett of Colorado, also a presidential candidate, has suggested a similar plan; in the first debate, Mayor Pete Buttegieg said, "the right kind of soil management and other kind of investments, rural America could be a huge part of how we get this done."
The fact that anyone is talking about soil health on the national stage is so exciting I can hardly stand it! But we need more than voluntary efforts from farmers, since the farm lobby has fought similar efforts in the past. And we need to make sure that these problems are addressed in a comprehensive way. If we’re talking about soil, we need to be talking about fertilizer too. If we’re talking about run-off to decrease salinity, then we need to talk about coral reefs.
All of these problems are part of the same problem: our problems aren’t geographically or economically isolated. Our indifference to the value of our resources – soil, water, coral reefs – threatens our own success and survival. If we lose coral reefs, we lose more than coral: coral reefs cover less than 1 percent of the ocean floor, but they support about 25 percent of all fish species; worldwide, more than 500 million people depend on coral reefs for food, income, coastal protection, and more; coral reefs protect us from flood damages, representing $94 million in savings.
This is how coral reefs help protect us from storm surges and what happens if they aren't there.
More than a quarter are already gone.
In other news, here's a fun reminder: my book comes out in 4 weeks and 6 days! Please don't miss your opportunity to pre-order! You can find all the links to buy it here.
Here's what else I'm reading:
Check out these floating Dutch dairy farms because hey why not! (Quartz)
And restoring peat bogs in the UK could be yet another effective carbon-sequestering solution. (BBC)
The government is suing Duke Energy for environmental damages caused by a coal ash spill 5 years ago! (AP) (If you know me/coal ash/me&coal ash, you know why this is huge!)
Also, in last week's issue, I made a mistake! When I wrote about the NASA instruments that detect sea level rise, I wrote, "...2 of those 3mm are the result of sea levels rising, and 1mm is the result of the heating of the upper ocean (liquids expand when they get hotter)." But that was imprecise. What I meant was that 2mm of those 3mm are from more water being added to the ocean (from melting ice), and the 1mm is result of heating of the upper ocean. Taken together, these two measurements account for the total 3mm of sea level rise. Thank you to Dr. Freilich for pointing this out!
See you next time! Oh and if I didn't mention it, please pre-order my book and also tell everyone you know to do the same!
Tatiana
Find more of my work here.