Allergy season is getting longer—and other surprising takeaways from Friday’s big climate change report

As seasons shift, so do pests. The report indicates that as weather patterns change, pests’ territories will expand. That means disease-transmitting mosquitoes will make it further north before dying, and ticks carrying Lyme disease will further fan out across the U.S. Parts of the country where farmers rely on a long, cold winter to kill off weeds and invasive species will have to adapt. (Weeds, by the way, really like high concentrations of CO2. They’re expected to thrive under changing conditions. The same is true for “weedy” fish—the hearty, non-delicious species that can survive on anything. Think cockroaches of the sea.)

Also, allergy season will get longer, and plants like ragweed—which is particularly allergenic—will proliferate.

Sometimes, it’s just too damn hot.

In 2010, the dairy industry lost an estimated $1.2 billion in productivity due to “heat stress,” a phenomenon that afflicts cattle during the summer. When it’s hot outside, cows are less hungry, and they digest food at a different rate. That means they produce less milk. If the animals don’t have access to shade or air conditioning, the effect worsens. As summers get hotter, the financial damages wrought by heat stress on the dairy industry are expected to hover around 1 percent over the next 12 years. Beef cows and other livestock are affected, too, but many are already grown in temperature-controlled settings.

It all adds up to less productive farms …

The above are just a few impacts of climate change on agriculture outlined in the report. Others—erosion, crop loss caused by extreme weather events—will be just as impactful. Overall, the climate assessment indicates, agricultural productivity will suffer.

… and less farmland overall.

According to the report, the amount of land developed for “urban” use will increase by 50 percent and the land developed for suburbs will increase by 80 percent by 2050. That means we’ll lose between 520,000 and 600,000 square miles of land that’s currently being used for agriculture or is otherwise undeveloped.

A major increase in developed land also means tons of other food-growing factors will be impacted. In California, for instance, demand for water in developed areas is expected to increase by 60 percent by the end of this century. That means increased competition for already-scant resources, which may lead to political tensions and thirstier crops.

Underwater habitats are in jeopardy, too.

Just like on land, climate change results in habitat shifts for common food fish in the sea. Because people don’t move as easily as migratory species, that may cause problems in the future. Fishermen in Massachusetts can’t exactly set up shop 300 miles north if cod decide they like it better in Canada.

As with the temporarily high corn yields in the U.S., the future result of these shifts looks mixed. For instance, while “catch potential” in the Bering Sea is forecasted to increase by 46 percent, populations of pollock, a key species caught in that region, are expected to decline. Lobsters, which represent the most valuable fishery in this country, are also going to be harder to find.

Other related phenomena like ocean acidification are already impacting fish stocks. As I wrote last year, baby oysters in the Pacific Northwest struggle to build their shells because of the shift in marine chemistry.

Because many communities around the world depend on the commercial fishing industry, changing population dynamics and migratory patterns have an outsized impact on local economies.

Will cellulosic bioenergy save us all? Not by 2020.

Remember back when ethanol derived from corn was supposed to replace gasoline and propel us into a carbon-neutral future? Fast forward a few years and we’ve still got the ethanol mandate—which puts a lot of money in the pockets of the Archer Daniels Midlands of the world—but, as Grist points out, “among environmentalists … the growing consensus is that corn-based ethanol is more fool’s gold than eco-treasure.” That’s because the agricultural methods used to grow vast quantities of corn rely on lots of pesticides and fertilizers, which run off into our water sources and are produced using carbon dioxide.

There’s another type of biofuel that holds a lot of promise but hasn’t yet reached its potential. It’s called cellulosic biofuel. This is a catch-all term for a process that involves using material like switchgrass or paper pulp to make fuel. Researchers are hopeful it could even be made from the parts of the plant left over after corn or sugarcane crops are harvested.

According to the climate assessment, research on cellulosic bioenergy crops has already been conducted in experimental fields. But we’re a long way from feeding switchgrass into our gas tanks. And downstream, “cascading” impacts that might result from devoting more farmland to fuel production remain unclear.

What else can farmers do to mitigate climate change?

Agriculture accounts for about 9 percent of U.S. greenhouse gas emissions, so changes made in the farming sector could have a major impact. According to the report, the changes farms can make to sequester more carbon are pretty much exactly what the federal government already recommends: planting cover crops, integrated pest management, and so on.

The report also says genetically modified crops show some promise, but the complicated politics and property rights inherent in any large-scale adoption of GMOs—not to mention the considerable amount of time it takes to bring a new seed to market—limit the technology’s potential.