The relationship between climate change and agriculture is unfortunately a two-way street. Because of fertilizer use, the tilling of soil, livestock production and manure management, the US agricultural sector contributes nine percent of the nation's greenhouse gas emissions. Globally, if you add in the effects of agricultural land use, namely deforestation, that number jumps up to possibly a third of emissions. Conversely, agriculture is clearly susceptible to climate change, whether through shifts in precipitation including droughts and floods, more frequent and longer heat waves and increased threats from pests and disease.

Climate change could soon have some dire repercussions for our food system. As a recent study published in Nature found, if there are no significant reductions in carbon emissions, heat increases would cut the US wheat crop by 20 percent, soybeans by 40 percent and corn by 50 percent by the end of the century. As the report authors point out, because the US is a major exporter of these three crops, it wouldn't just be Americans who would suffer since "world market crop prices might increase, which is an issue for food security in poor countries."

The science on climate change, and the associated risks that our food system faces, is clear. Despite what some elected officials might say, the majority of Americans accept climate science: 70 percent of American adults think global warming is happening. However, only 40 percentthink global warming will harm them personally. That's yet more evidence that the slow-moving and abstract threat of climate change is perfectly designed for humans to ignore. But knowing the current and future impacts of climate change on our food system, how should we prepare to meet the threat? A good first step is to look back 200 years in the past, when the world had a brief flirtation with climate change.

The 1815 eruption of Mount Tambora in Indonesia is considered the largest volcanic eruption in recorded history and caused widespread climate disruption around the world. The particles from the volcano made their way into the stratosphere and temporarily dropped the average global temperature by three degrees Celsius. The following summer in Europe, Asia and the Northeastern US was filled with cold rain and snow, crops failed and food prices soared.

While the worldwide effect of the Tambora eruption is well-documented, a recent study looked specifically at the long-term impacts on fisheries in the Gulf of Maine, and it turns out that what may seem like a small part of the story has some big lessons. In the early 1800s, alewife, a small "utility" fish, were a crucial part of the New England food system, used for everything from fertilizers to food. But alewife did not fare well during 1816's "Year Without a Summer," and with livestock dying and crop yields dropping by a devastating 90 percent, New Englanders were desperate. Fishermen shifted their catch to mackerel, an abundant species easily caught near the coast and much less vulnerable to sudden shifts in climate. New Englanders took to the fish, and even though alewife recovered 25 years later, mackerel continues on as a major regional fishery.

The parallels to problems from climate change we see today and anticipate in the future are many. After devastating crop losses in 1816, many New Englanders were forced to move, just as we've recently seen people do in drought-ravaged Syria and increasingly flood-prone Pakistan. Large numbers of people in the Northeast US were dependent on alewife in the early 19th century, just as today a billion people across the globe depend on fish for protein. And just as failed crops and fisheries in New England were once exported to neighboring regions, we now have predictions for large crop reductions in the US which will impact our exports of food to other parts of the world.

We know that we're facing a looming crisis in the future, and most of us accept the reasons behind it, so what should we do? Within the food system there must be a combination of curbing greenhouse gas emissions and becoming more resilient to anticipated changes. Fortunately, both of these can be addressed at the same time through "climate-smart" agriculture techniques such as reducing water use, planting a diverse array of climate-appropriate crops, improving soil management and installing green infrastructure to store carbon and manage rainfall. On the coast, fishermen will need assistance to adapt as once-abundant species diminish or migrate because of climate change, and fisheries around the world will need to be better managed to feed those who depend on fish as a key part of their diet. The industrialized nature of America's food system makes it particularly vulnerable to any shifts to water, energy or land resources, so there must be a movement towards a more resilient regional food system.

Unlike the Tambora eruption, the current climate change threat is not immediate, so there is a window (although limited) in which we can plan for the agricultural challenges ahead. Humans may not be hard-wired to deal with slow, simmering problems, but looking back on how just one corner of the world dealt with a sudden shift in climate can give us plenty of ideas for how to prepare.