The US Global Change Research Program just released Volume II of the Fourth National Climate Assessment (NCA4-II). News stories on this report have focused on the report’s “dire” and “grim” predictions. Problem is, NCA4-II does not predict anything. Rather, the report explores possible futures based on different “scenarios”, which it says “are never predictions nor forecasts”. Depending on what scenario is used, the effects of climate change range from the manageable to the awful. The worst-case scenario used in NCA4-II is only within the realm of the plausible if you assume a reversal of current mitigation and adaptation trends. As in embracing fossil fuels in all their emitting glory and forgetting about CO2 capture/storage - even though renewables are getting cheaper and cheaper and the cost of carbon capture is plummeting. As in farmers accepting reduced yields and not working like crazy to increase crop resilience to the vagaries of climate.
Enough of implausible scenarios! Onward to the hopeful parts of NCA4II - namely, what is being done and what can be done to adapt to the potential effects of climate change – as per the report itself. This time….
Excerpts from Chapter 10: Agriculture and Rural Communities
Recent advances in precision irrigation technologies, improved understanding of the impacts of different dryland and irrigation management strategies on crop productivity, and the adoption of weather-based irrigation scheduling tools as well as drought-tolerant crop varieties have increased the ability to cope with projected heat stress and drought conditions under climate change.
Because increased precipitation extremes elevate the risk of surface runoff, soil erosion, and loss of soil carbon, additional protective measures are needed to safeguard the progress that has been made in reducing soil erosion and water quality degradation from U.S. croplands through the implementation of grassed waterways, cover crops, conservation tillage, and waterway protection strips). Conservation strategies that are being implemented to reduce soil erosion and increase carbon sequestration use the estimates of expected average climate conditions derived from historical data.
In the absence of migration of livestock production to more temperate climates, adaptation strategies are possible to a degree. For example, as local temperatures increase, livestock can be genetically adapted to local conditions. However, the physical mitigation of heat stress in livestock often requires long-term investments such as climate-controlled buildings, portable or permanent shading structures, and planted trees, as well as short-term production strategies such as altering feeds.
Studies have shown that shading in combination with fans and sprinkler or evaporative cooling technologies can mitigate the short-term effects of heat stress on animal production and reproductive efficiency. Other strategies include aligning feeding and management practices with the cooler times of the day and reducing the effort required by animals to access food and water.
The Agricultural Model Intercomparison and Improvement Project (AgMIP) applies state-of-the art climate, crop/livestock, and agricultural economic models, along with stakeholder input, to coordinate multimodel regional and global assessments of climate impacts and adaptation. AgMIP is developing a rigorous process to evaluate agricultural models and thus is promoting continuous model improvement as well as supporting data sharing and the identification of adaptation technologies and policies.
Considerable private- and public-sector research is focused on the genetic improvement of crops to enhance resilience under climate stress. …Agriculture has the ability to mitigate greenhouse gas emissions through carbon sequestration in the soil and perennial vegetation, through improved nutrient-use efficiency of fertilizers, and through reduced methane emissions from ruminant livestock and manure.
Yes, major challenges remain. Lots more to do. Lots we don’t know yet. But uncertainty doesn’t mean to wait and do nothing until the future is clear. Uncertainty means you move forward and make adjustments as the future reveals itself. Which means you want to avoid doing things that reduce the scope of action later on.
Next: Conclusion of this series: The problem with ‘We Must Act Now!’