Agriculture and the Iris Hypothesis | The Climate Debate in Ireland

The United States is one of the most well-known, openly publicised countries whose citizens, businesses and politicians are constantly in the throes of the climate debate. A staggering 31% of Americans believe that global warming is a result of natural causes and not due to human activity, while the 20% believes there is no solid evidence of global warming happening at all.

While it is easy to believe this debate is primarily localised in America, we are seeing more individuals speaking out against the validity of climate change in Ireland. Matt Dempsey, the former editor of the popular publication “The Farmer’s Journal”, has recently expressed views on the increasingly popular debate on climate change here in Ireland.

In his article addressing his doubts about the severity effects of climate change, he leads with the question:

“Is the science on climate change sound enough to justify Ireland facing into an enormous ongoing diminution of our agricultural sector?”

As seen above, there are two aspects to this question – is the science right about global warming, which is regarded by many published scientists to be happening at an unprecedented rate due to human activities, and will it cause severe cuts in our agriculture sector.

To start, let’s address the first aspect. Dempsey states that his doubts about the misconception of the severity of global warming first stemmed from a lecture he attended by a former professor of Massachusetts Institute of Technology, Richard Lindzen. The main points Dempsey took from Lindzen’s lecture are detailed below.

“The key point for me was the statement that methane produced by cattle and sheep and nitrous oxide produced in tillage operations have very little role in whatever global warming is taking place. The point was made that naturally occurring water vapour in the atmosphere is thousands of times more plentiful than these gases and its greenhouse effect vastly outweighs any additional effect they could have.”

Now when Dempsey speaks about water vapour being more potent than we realise at outweighing the greenhouse effect, he is referring to one of Lindzen’s theories – The Iris Hypothesis. This hypothesis depicts that as sea surface temperatures increase in the Tropics, cloud cover decreases, specifically by 22% per degree. This hypothesis goes on to state that the reduced cloud cover will lead to more infrared radiation leaking from our atmosphere, producing a cooling effect which can balance global warming.

While there was a correlation between cloud cover and sea surface temperatures in Lindzen’s results, his conclusion as to whether it will counteract global warming is still a hypothesis. A hypothesis is a proposed explanation that has not yet stood the test of time against repeated replications which yield highly similar results for every replicate.

It has not gained the status of a theory or law yet in the scientific community. In fact, there has been a study done on The Iris Hypothesis which suggests there is no evidence supporting it at all. Additionally, Bing Lin, an atmospheric scientist at NASA, described the hypothesis as “exciting”, but states that NASA’s Clouds and the Earth’s Radiant Energy System (CERES) sensor got completely different results from Lindzen, reporting a slight increase in surface temperature due to increased cloud cover opposed to a decrease.

There is some support for Lindzen’s Iris hypothesis, but overall the results have been inconclusive as to whether there is a balancing climatic effect happening on Earth.

Meanwhile, on average over 96% of specialised climate scientists agree that global warming has risen since pre-1800 levels and that human activity is contributing to this warming.

Hockey Stick Graph -
The Famous Hockey Stick Graph. Source

The EPA not just in the United States, but in Ireland too, states the our climate is changing. These changes are more recently attributed to human factors through greenhouses gases being produced like carbon dioxide, methane, and nitrous oxide and additionally due to the destruction of forests which take in carbon dioxide.

The climate has changed in past before this, but not at the current rate we are seeing today.

There is enough evidence supporting climate change, that it at least warrants the respect for a response as to how we are going to mitigate it. If Lindzen’s hypothesis is correct, that will help, the mitigation process immensely, however, we should take proper action to help reduce our emissions regardless in order to ensure the protection of the future productivity of our plant.

This includes the productivity of our agricultural sector. This brings me to the second aspect of Dempsey’s proposed question.  Will climate change cause severe cuts in our agriculture sector?

It is true that our agricultural sector is the biggest emitter of greenhouse gases in Ireland. The majority of the emissions occurs from cows, fertilisers and transport/machinery.

However, a comprised agricultural sector will impact Ireland. The sector fills our supermarkets and contributes to over 13 billion euro to our exports and employs 8.5% nationally. Climate change, the finite fuel industry and emissions compromises our agricultural sector through the increased severity of floods and storms as well as more far-reaching consequences such as the reversing of the Gulf-stream that keeps us ice-free year round.

Rather than debating whether the belief of climate change is a threat to the agricultural industry in Ireland, we should be using climate change as a driver to propel Ireland into new advancements in technology and progressive policies that will greatly expand and secure our agricultural sector past any previous limiting constraints.

Cross-breeding cows to lower producing methane varieties could set to be of huge value to expanding agricultural industry. Additionally, organic fertilisers, such as insect based types would lower the amount of nitrous oxide being produced from using less nitrogen based fertilisers, as well as inter-cropping vegetation with specialised nitrogen fixing plants such as legumes. Renewable energy is only set to become a more prominent industry globally, as the finite fuel resources are slowly used up.

These are only a handful of the possible measures that can be taken in order to reduce our emissions but at the same time promote a sustainable growing agricultural industry in Ireland. More research and proper incentives are needed to ensure the proper execution of such mitigation strategies, but with cooperation and open discussion, we can evolve into being one of the world’s leading agricultural industries, both in productivity and sustainability.

All that is left for us is to debate how we are going to live with climate change – not whether if it’s really happening or not.

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