On Thursday, President Donald Trump announced the United States is withdrawing from the Paris climate accord, a global effort to reduce greenhouse emissions to limit global warming to an increase of two degrees Celsius.

The decision ended the country’s involvement in the agreement, which was the most significant treaty ever to address combatting climate change.

In December 2015, University of Illinois Crop Sciences Professor Stephen Long addressed the Paris Climate Change Conference to explain the impact of climate change and a growing population on agriculture across the globe. Long is considered one of the world’s leading experts on crop science, and has been called one of the world’s “most influential scientific minds” by Reuters. His current research includes increasing the efficiency of the photosynthesis to increase plant yield.

The Midwest Center for Investigative Reporting spoke with Dr. Long to discuss what the United States pulling out of the treaty means for agriculture across the Midwest and the globe.

Below is a lightly edited transcript of the conversation.

Investigate Midwest: When you spoke to the Paris convention in December 2015, what did you say?

Stephen Long: In Paris, what I was presenting on was the impacts of atmospheric and climate change on the major crops – corn, soybeans, wheat and rice, and the means by which we might adapt to those changes and how to do it.

IM: Were people receptive to your message?

SL: Yes. They were. There was certainly a lot of interest in it. It was just one small part of the Paris talks.

IM: How would that message change today?

SL: The United Nations Food and Agriculture Organization projects that by 2050 we're going to be needing to produce 70 percent more food than we are today. It's not just more population, but the world is moving to be more and more urbanized. Urban diets require more food because it's got to be transported, there is more waste. Urban diets generally have more meat and more dairy. If you look at current projections, we're not going to get there.

And all of that is going to be impacted by climate change.

Even an increase of two degrees (Celsius), that we agreed upon at Paris, will have huge impacts. For example, in some parts of the world, that could eliminate wheat production.

Going even higher than that by pulling out of this agreement creates more challenges.

IM: How big of a loss is this?

SL: At the moment, it is very significant. Not only is the U.S. one of the largest carbon dioxide emitters, countless other nations look at the U.S. for leadership, so there is a void there.

Already, Europe is stepping up to the plate. China stepping up to the plate. They will be leaders in bringing new technology. Already, they’re a leader in producing solar cells.

Pulling out of the agreement means the United States won’t be a leader in the future.

IM: Why do you think the current administration is not receptive to combatting climate change?

SL: There has always been a hard line in the Republican Party that believes that climate change is a myth, and it seems they have gotten the upper hand.

Even though coal production has decreased – and I’m no expert in that area – with the abundance of natural gas, the fate of energy seems to be fossil fuels.

As far as jobs in coal mining are concerned, we've gotten so much equipment that eliminate those jobs that I don't see those arguments as being particularly strong.

Not only is President Trump pulling out of the agreement, but he’s also proposed cutting the budget of the Department of Energy’s clean coal initiative that would be able to limit greenhouse gases even if we continue to use coal.

IM: What does this all mean for a farmer in the Midwest?

SL: Even with a two degree rise by 2050, we are going to see impacts in the Midwest. The reason this land is so productive is because it has this combination of climate and soil. The United States is one of the biggest exporter of primary food stuffs, and a lot of that has to do with the Midwest. A two degree rise means the ideal climate moves further north, which is better for Minnesota and Wisconsin farmers, but they don't have the soils we have in the current Corn Belt.

In the current climate projections, there are more challenges for Midwest productivity. We’re going to have wetter springs and very high rainfall and floods. In our area, we already see about 10 percent of the fields around here are still flooded. This was predicted 15 years ago by climate change models, and it’s come true.

As carbon increases in the atmosphere, there will be higher rates of evapotranspiration and to maintain yields, more and more irrigation will be required. This will put more pressure on water resources.

IM: How will climate change affect agriculture across the globe?

SL: We’re seeing that pollination and fertilization are very sensitive to temperature. In high temperatures, wheat production really goes down in Australia. It will likely lead to less production in parts of India and Mexico, even in some U.S. growing areas too. We could see this affecting the corn crop, and we’re not sure whether we can adapt it to those changes (higher temperature).

One factor that goes with coal production and fossil fuel use is the increase of the amount of carbon in the ozone. Already, the carbon in the ozone costs U.S. farmers about 8 percent of their corn yield. In other words, farmers could effectively be producing 8 percent more than they are, but they’re not, just because of ozone. With the U.S. pulling out of the Paris agreement, that’s not going to change, and it could get worse.

IM: As a crop scientist, are you going to be able adapt crops to higher temperatures?

SL: It’s really uncertain. A lot of research is going to be needed to be able to adapt to these, and, the Trump administration has proposed budget cuts to the National Science Foundation and USDA, so we’re not going to see research coming from there.

In our work with the Bill and Melinda Gates Foundation, we’re working on crops in Sub Saharan Africa that can adapt to higher CO2 levels and evapotranspiration. But it will be at least 20 years until those crops will be in farmers’ fields at scale.

Areas that might have been able to help this research prosper are proposed for major cutbacks in the president’s proposed budgets.

It was a big deal that the United States joined. Many other nations likely signed on because of U.S. involvement, and now this.

IM: Is there any reason for hope or anything that people can do?

SL: There is reason to hope. A number of corporations are stepping up to the plates to reduce their fossil fuel use and become climate neutral. People can support those corporations.

In the past, we’ve talked a lot about GMO labeling, but maybe we should consider green labeling that way people can support those corporations that are supporting the environment.

IM: Even though President Trump pulled out of the agreement, could the damage be reversed? Could the United States still reach the goals set out by the Paris Climate Agreement?

SL: It’s possible the U.S. could reach its goal if enough major companies step up to the plate to reduce their fossil fuel use and reduce their energy use. If they invest enough money in research and technology development, including in using decarbonized fuels.

I also I don’t think it’s impossible if states step up to the plate. Already, some have said this isn’t going to alter their policy, including the governor of California.

Is there anything else people need to know?

SL: Climate change is portrayed as having a lot of uncertainties in the in the media, especially media really represents the right wing. While it's correct to say there are uncertainties, we do know some facts. We know the temperature is rising. It’s a physical fact that carbon dioxide is rising and the levels of CO2 have almost doubled over the levels from the past 25 million years. We know it’s fossil fuels that have caused this rise.

Carbon Dioxide is a greenhouse gas, and increasing levels in the atmosphere traps more energy, meaning the earth has to warm.

Where the uncertainties are is in the effects – where rising temperatures will occur, what it will do to rainfall and drought. But it’s a basic law of physics that the earth has to warm.