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While all sectors of the economy can be impacted by climate variability and change, the agricultural sector is arguably the most tightly coupled to climate where changes in precipitation and temperature directly control plant growth and yield, as well as livestock production. This paper analyzes the direct and cascading effects of temperature, precipitation, and carbon dioxide (CO2) on agronomic and horticultural crops, and livestock production in Indiana through 2100. Due to increased frequency of drought and heat stress, models predict that the yield of contemporary corn and soybean varieties will decline by 8–21% relative to yield potential, without considering CO2 enhancement, which may offset soybean losses. These losses could be partially compensated by adaptation measures such as changes in cropping systems, planting date, crop genetics, soil health, and providing additional water through supplemental irrigation or drainage management. Changes in winter conditions will pose a threat to some perennial crops, including tree and fruit crops, while shifts in the USDA Hardiness Zone will expand the area suitable for some fruits. Heat stress poses a major challenge to livestock production, with decreased feed intake expected with temperatures exceeding 29 °C over 100 days per year by the end of the century. Overall, continued production of commodity crops, horticultural crops, and livestock in Indiana is expected to continue with adaptations in management practice, cultivar or species composition, or crop rotation.

The Indiana Climate Change Impacts Assessment (IN CCIA) is a collaborative effort to provide professionals, decision makers, and the public with information about how climate change affects state and local interests throughout Indiana, USA. This assessment effort has three interrelated goals: (1) analyze and document the best available climate change impacts research, (2) develop and maintain a network of stakeholders and experts, and (3) start a dialog about climate change throughout Indiana. The project adopted a process that prioritized stakeholder engagement, re-envisioned traditional dissemination approaches, and that had limited state government involvement, setting the IN CCIA apart from most other state climate assessments (SCAs) in the USA. This overview describes the motivations, principles, and processes that guided the IN CCIA development, explores how Indiana’s approach compares with those of other SCAs, and briefly summarizes the papers presented in this special issue. As interest in SCAs grows in non-coastal and politically conservative locations, the IN CCIA serves as one example of how a bottom-up assessment with limited funding can deliver credible climate science to diverse stakeholder groups in the absence of state-level mandates or direction and attract public attention over an extended period of time.

Static thermal requirements (Treq) are widely used to model the timing of phenology, yet may significantly bias phenological projections under future warming conditions, since recent studies argue that climate warming will increase Treq for triggering vegetation phenology. This study investigates the temporal trend and inter-annual variation of Treq derived from satellite-based spring and autumn phenology for the alpine and temperate vegetation on the Tibetan Plateau from 1982 to 2011. While we detected persistent warming in both spring and autumn across this time period, we did not find a corresponding long-term increase in Treq for most of the study area. Instead, we found a substantial interannual variability of Treq that could be largely explained by interannual variations in other climatic factors. Specifically, the number of chilling days and fall temperature were robust variables for predicting the dynamics of Treq for spring onset and autumn senescence, respectively. Phenology models incorporating a dynamic Treq algorithm performed slightly better than those with static Treq values in reproducing phenology derived from SPOT-VGT NDVI data. To assess the degree to which Treq variation affects large-scale phenology and carbon cycling projections, we compared the output from versions of the Terrestrial Ecosystem Model that incorporated static and dynamic Treq values in their phenology algorithms. Under two contrasting future climate scenarios, the dynamic Treq setting reduced the projected growing season length by up to 1–3 weeks by the late twenty-first century, leading to a maximum reduction of 8.9 % in annual net primary production and ~15 % in cumulative net ecosystem production for this region. Our study reveals that temporal dynamics of Treq meaningfully affect the carbon dynamics on the Tibetan Plateau, and should thus be considered in future ecosystem carbon modeling.

Fossil fuels developed from ancient deposits of organic material, and thus can be thought of as a vast store of solar energy from which society meets >80% of its current energy needs. Here, using published biological, geochemical, and industrial data, I estimate the amount of photosyntheti- callyfixed and stored carbon that was required to form the coal, oil, and gas that we are burning today. Today's average U.S. Gallon (3.8 L) of gasoline required approximately 90 metric tons of ancient plant matter as precursor material. The fossil fuels burned in 1997 were created from organic matter containing 44 × 10 18 gC , which is>400 times the net primary productivity (NPP) of the planet's current biota. As stores of ancient solar energy decline, humans are likely to use an increasing share of modern solar resources. I conservatively estimate that replacing the energy humans derive from fossil fuels with energy from modern biomass would require 22% of terrestrial NPP, increasing the human appropriation of this resource by ∼50%.