USDA Ag Outlook Forum - Climate change

All of the presentations from the second day of the Feb. 21-22 Agricultural Outlook Forum have been posted, and here is one that caught my eye:

How will global climate change affect agriculture? This 37 page pdf by Jerry Hatfield of the National Soil Tilth Laboratory of Ames, Iowa, speculates about climate change in the next 10 to 30 years.
Here is a quick summary:
- Increasing temperature of 1.2C (2.2F) over the next 30 years
- Increasing CO2 of 60 ppm over the next 30 years
- Increasing variability in precipitation
- There will be increasing variation in temperature and precipitation within and among years

The plant response will be mixed, he said:

Occurrences of higher temperatures will
cause faster phenological development
- Higher temperatures will affect reproductive development because of the sensitivity of pollen survival to temperature
- Yields will be impacted because of shorten reproductive periods

For fruits and nuts:
- Warmer temperatures will cause earlier bud break or flowering in the spring
- Warmer temperatures will cause faster development
- Warmer temperatures could impact chilling requirements for many plants
- Increase potential problems when warm temperatures cause early development and then turns cold


On CO2
- Increasing CO2 will increase plant growth
- Difference between C3 and C4 plants
- Increasing CO2 will increase water use efficiency because of increased growth per unit of water transpired

On precipitation
- Variable precipitation will increase potential soil deficits
- Decreased soil water availability will offset the positive impacts of CO2 and exaggerate the effect of increasing temperatures

On pests
- Weeds will be favored by increased CO2
- Increased temperatures will change phenological development of weeds
- Increased spring, winter, and fall temperatures will allow for winter survival and earlier seasonal onset of insects and pathogens

Implications

Implications
- Temperature increases will alter phenological development of crops, increase potential sensitivity to temperature extremes in fruit crops
- Temperature increases will affect reproduction because of sensitivity of pollen
to extreme temperatures
- Overall impact will be to decrease crop yield and forage quality
- Temperature increases will negatively impact animal production and reproduction
- Increasing CO2 will positively impact plant growth and ultimately yield
- Increasing CO2 will reduce crop water use which will be an advantage under water limitations
- Increasing CO2 will offset some of the negative impacts of increasing temperature

Management Changes
- Producers can adapt to climate changes by altering crop management practices, e.g., planting date, crop selection, nutrient management
- Producers can adapt to climate changes in livestock through changes in management practices that reduce exposure to thermal stress


TK: All in all, more bad than good, and 2.2 degree rise in temperature over the next 30 years is a steep increase.