Sectoral Impact Analysis Methodology within the Scope of Climate Change Adaptation

GI multisociety strategic plan on environmental sustainability.

Climate change is the most important challenge in achieving sustainable development. Semi-arid and arid areas (such as Iran) are particularly susceptible to the effects of climate change on water supply. In this research, the effect of climate change and upstream land use is investigated on Tajan, a river in the north of Iran. The data regarding the climate were produced via second-generation Canadian Earth System Model (CanESM2) and adopted as the input to SWAT hydrologic model under RCP2.6 and RCP8.5 for the period of 2016–2066. The results showed that the peak streamflow will increase by 4% and 5.7% and the average annual discharges will decrease by 16% and 16.5% from 2016 to 2066 for RCP2.6 and RCP8.5 scenarios, respectively. Besides, the effect of different land use change scenarios on streamflow was investigated under four diverse scenarios selected to represent a comprehensive range of possible land use map of the basin. Land use change scenarios led to 8.5–15.8% increase in the average annual streamflow, highlighting the fact that it is less effective than climate change on streamflow. It could be concluded that downstream water users in the basin should adopt strategies to cope with water-stressed condition under the changing climate.

We evaluated how climate change and variable rates of moose browsing intensity, as they relate to wolf predation, might impact the forests of Isle Royale National Park, MI USA by conducting a simulation modelling experiment. The experiment consisted of contrasting three different scenarios of wolf management and with a static (current conditions) and changing climate (high emissions). Our results suggest that the interactive effects of wolf predation and climate change are likely to be temporally variable and dependent on biogeographic and forest successional processes. During the first 50 years of simulations, when the effects of climate change were minor, higher simulated rates of predation by wolves reduced moose population densities, resulting in greater forest biomass and higher carrying capacities for moose. However, over the longer term, early successional and highly palatable aspen and birch forests transitioned to late successional spruce and fir forests, regardless of climate or predation intensity. After 50 years, the effects of climate change and predation were driven by effects on balsam fir, a late successional species that is highly palatable to moose. High-intensity predation of moose allowed balsam fir to persist over the long term but only under the current climate scenario. Climate change caused a reduction in balsam fir and the other boreal species that moose currently feed on, and the few temperate species found on this isolated island were unable to compensate for such reductions, causing strong declines in total forest biomass. The direct effects of moose population management via reintroduction of wolves may become increasingly ineffective as the climate continues to warm because the productivity of boreal plant species may not be sufficient to support a moose population at all, and the isolation of the island from mainland temperate tree species may reduce the likelihood of compensatory species migrations.

We assessed the effects of historical (1931–1998) changes in both land use and climate on the water budget of a rapidly urbanizing watershed, Ipswich River basin (IRB), in northeastern Massachusetts. Water diversions and extremely low flow during summer are major issues in the IRB. Our study centers on a detailed analysis of diversions and a combined empirical/modeling treatment of evapotranspiration (ET) response to changes in climate and land use. A detailed accounting of diversions showed that net diversions increased due to increases in water withdrawals (primarily groundwater pumping) and export of sewage. Net diversions constitute a major component of runoff (20% of streamflow). Using a combination of empirical analysis and physically based modeling, we related an increase in precipitation (2.7 mm/yr) and changes in other climate variables to an increase in ET (1.7 mm/yr). Simulations with a physically based water‐balance model showed that the increase in ET could be attributed entirely to a change in climate, while the effect of land use change was negligible. The land use change effect was different from ET and runoff trends commonly associated with urbanization. We generalized these and other findings to predict future streamflow using climate change scenarios. Our study could serve as a framework for studying suburban watersheds, being the first study of a suburban watershed that addresses long‐term effects of changes in both land use and climate, and accounts for diversions and other unique aspects of suburban hydrology.

Climate change is a public health emergency.1Solomon CG LaRocque RC Climate change–a health emergency.N Engl J Med. 2019; 380: 209-211Crossref PubMed Scopus (75) Google Scholar Clinicians worldwide now face the reality of caring for patients during wildfires, heat waves, floods, and shifting infectious disease patterns. Health-care workers need better preparation to care for communities facing the health effects of climate change.2Salas RN The climate crisis and clinical practice.N Engl J Med. 2020; 382: 589-591Crossref PubMed Scopus (22) Google Scholar Medical students have been key advocates in these efforts, driving research, community partnerships, and education.3Goshua A Gomez J Erny B et al.Addressing climate change and its effects on human health: a call to action for medical schools.Acad Med. 2021; 96: 324-328Crossref PubMed Scopus (44) Google Scholar, 4Fadadu RP Jayaraman T Teherani A Climate and health education for medical students.Clin Teach. 2021; 18: 362-364Crossref PubMed Scopus (7) Google Scholar, 5Baker N Bromley-Dulfano R Chan J et al.COVID-19 solutions are climate solutions: lessons from reusable gowns.Front Public Health. 2020; 8590275Crossref Scopus (20) Google Scholar When we began medical school during record-setting Californian wildfires and a global pandemic, our curriculum did not address the effect of climate change on human health, nor the disproportionate effects on communities made vulnerable by racism and poverty. Here, we detail how we integrated the effects of climate change on health into more than a dozen courses at our institution, starting with the preclinical curriculum and then progressing through all levels of training. In this Comment, we use the example of reproductive health and obstetrics and gynaecology education to describe this longitudinal approach. Our student team first addressed the preclinical curriculum, highlighting the effect of climate change on disease pathophysiology across human health. We began with a review of our required preclinical curriculum, identifying areas of opportunity for integration on the basis of peer-reviewed literature. We worked closely with course faculty leads to incorporate climate topics into pre-existing course materials using an equity lens, emphasising the disproportionate health effects of climate change on low-resourced communities.4Fadadu RP Jayaraman T Teherani A Climate and health education for medical students.Clin Teach. 2021; 18: 362-364Crossref PubMed Scopus (7) Google Scholar, 5Baker N Bromley-Dulfano R Chan J et al.COVID-19 solutions are climate solutions: lessons from reusable gowns.Front Public Health. 2020; 8590275Crossref Scopus (20) Google Scholar, 6Nardone A Casey JA Morello-Frosch R Mujahid M Balmes JR Thakur N Associations between historical residential redlining and current age-adjusted rates of emergency department visits due to asthma across eight cities in California: an ecological study.Lancet Planet Health. 2020; 4: e24-e31Summary Full Text Full Text PDF PubMed Scopus (164) Google Scholar For example, we supplemented our reproductive health course with lecture slides identifying air pollution and heat exposure as environmental teratogens that increased the risk of adverse birth outcomes, especially for Black women and people with asthma.7Bekkar B Pacheco S Basu R DeNicola N Association of air pollution and heat exposure with preterm birth, low birth weight, and stillbirth in the US: a systematic review.JAMA Netw Open. 2020; 3e208243Crossref PubMed Scopus (257) Google Scholar Transitioning to clinical integration, our team expanded on knowledge gained in the preclinical setting to teach students how to identify climate-related disease pathology. In the obstetrics and gynaecology clerkship, we integrated climate and health effects into relevant didactic sessions and case presentations. For example, we highlighted how wildfire smoke contributes to preterm birth in our home state of California, USA.8Heft-Neal S Driscoll A Yang W Shaw G Burke M Associations between wildfire smoke exposure during pregnancy and risk of preterm birth in California.Environ Res. 2022; 203111872Crossref PubMed Scopus (37) Google Scholar Students also learned how to discuss climate-related topics in patient encounters. Lastly, we extended our efforts into the education of junior doctors, aiming to equip junior doctors with tools to counteract climate change's impacts on patients. These efforts emphasised how climate and health presentations are rooted in upstream factors that contribute to health inequities. For example, we developed a didactic session for the obstetrics and gynaecology junior doctor programme focused on taking environmental histories, providing climate-related patient education, and connecting junior doctors with advocacy resources.9Program on Reproductive Health and the EnvironmentPrenatal exposure to toxic chemicals and climate change.https://prhe.ucsf.edu/figoDate: 2022Date accessed: January 21, 2022Google Scholar Given the vital role that junior doctors play in medical student education, these efforts will not only provide junior doctors with tools to care and advocate for patients affected by climate change, but will also be passed down to medical students during clinical rotations. Although we use the obstetrics and gynaecology curriculum as an example of our longitudinal approach to climate and health education, our work has spanned across more than a dozen courses to date. Five best practices were crucial to our success: setting tangible education objectives as defined by the School of Medicine administration and relevant national climate educational efforts allowed us to develop targeted, effective educational interventions;10Fadadu R Hampshire K Ndovu A Medical students as agents of change in the climate crisis.Acad Med. 2022; 97: 1104-1105Crossref PubMed Scopus (3) Google Scholar soliciting iterative feedback from faculty and trainees enabled us to benchmark the school's progress in planetary health education; aligning with the Deans of Curriculum and Scholarship gave us a platform to directly interact with course faculty leads and integrate our research systematically; grounding our work in local effects and health equity by collaborating with at-risk community members ensured our educational materials were relevant to our patient population and showed how climate change is one of many social determinants of health; and connecting with national student and physician groups such as Medical Students for a Sustainable Future and Physicians for Social Responsibility enabled us to share resources, knowledge, and best practices. As climate change forces the world to grapple with a new understanding of normal, it is crucial that clinicians are prepared for the novel health effects that climate change will have on the communities they serve. A longitudinal approach to climate and equity education throughout medical training aims to not only build competency and awareness on the effects of climate change on health, but also provide an equity frame (figure). This approach empowers clinicians to effectively counsel patients within hospitals in addition to advocating for resources and policies outside clinical walls to best protect the health of their communities, ultimately preparing trainees for a career rooted in social justice and health equity. We declare no competing interests. AJ and AL contributed equally.

CR Climate Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials CR 50:83-102 (2011) - DOI: https://doi.org/10.3354/cr01038 REVIEW Effects of climate variability and change on Chinese agriculture: a review Yue Li1, Declan Conway2,*, Wei Xiong1, Qingzhu Gao1, Yanjuan Wu1, Yunfan Wan1, Yan Li3, Silong Zhang3 1Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China 2School of International Development/Tyndall Centre for Climate Change Research, University of East Anglia, Norwich, NR4 7TJ, UK 3Water Resources Information Center, Ministry of Water Resources, Beijing, China *Email: d.conway@uea.ac.uk ABSTRACT: Evidence is reviewed from Chinese and international sources on the impacts of observed climate trends and extremes and of potential future climate change on agriculture. Recent climate behaviour in China shows progressive warming and complex patterns of precipitation variability and frequency of extreme events. Agricultural production data highlight substantial economic impacts from extreme climate events, with droughts causing the greatest effects on production. Observed warming has contributed to northward and northeastward expansion of winter wheat and maize cultivation, respectively. Multi-model climate change projections consistently predict warming throughout China and, with reasonable consistency, increases in precipitation across most of the country (averaging +5% to +7% by 2050, compared with 1961−1990). Studies of future climate change impacts on crops in China show a wide range of results, primarily due to differences among climate model projections, the methods used to assess crop impacts and whether the effects of CO2 fertilisation are included. Because of China’s large size and range of agro-ecological conditions, sensitivity and exposure can vary considerably, leading to complex spatial patterns of response. Crop type and variety, and whether a crop is irrigated or rain-fed also affect yield. The review highlights research priorities, which include the need to systematically monitor, retrieve and analyse observed data on climate−yield behaviour, compare results of different modelling approaches and climate scenarios, and integrate climate effects within a broader framing of food systems. KEY WORDS: Climate variability · Climate change · Climate impacts · Agriculture · Economic impacts · China Full text in pdf format PreviousCite this article as: Li Y, Conway D, Xiong W, Gao Q and others (2011) Effects of climate variability and change on Chinese agriculture: a review. Clim Res 50:83-102. https://doi.org/10.3354/cr01038 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in CR Vol. 50, No. 1. Online publication date: December 12, 2011 Print ISSN: 0936-577X; Online ISSN: 1616-1572 Copyright © 2011 Inter-Research.

Modelling impacts of changes in carbon dioxide concentration, climate and nitrogen deposition on carbon sequestration by European forests and forest soils

The impact of land use- and climate change on the managed eco-geomorphic balance in the Alps

<p>Climate change may be a relatively new phenomenon, but its effects are being felt throughout the world and having a significant impact on peoples’ lives in many countries. Some of those most keenly feeling the effects live in areas that are particularly vulnerable to destabilizing factors acting in conjunction with existing challenges. The effects of climate change are an exacerbating factor in sometimes already difficult lives. In some areas, the effects of climate change are or may become such that the inhabitants contemplate migration to find a more viable life elsewhere, either in their own country or in another country. It is by no means guaranteed that the effects of climate change will inexorably lead people, such as those in low-lying small island states, to migrate outside their country, particularly if there are adequate measures taken to mitigate and adapt to the effects of climate change. However, it is becoming increasingly clear that the potential for climate change-related migration is drawing near, if it has not already arrived, as a factor for some people’s decisions to migrate internally or externally. Some work currently underway considers approaches to dealing with climate change-related migration and the possible related issues around human rights protections and practical management. Climate change is an amorphous, complex and politically challenging issue for governments and stakeholders to deal with. Its effects on peoples’ lives can be significant, especially in conjunction with existing development, environmental, and economic challenges. It is important to ensure that any approach created is necessary, in light of existing mechanisms and available resources, and that it does not disadvantage any other groups of people through its creation or functioning. This thesis considers the state of the international approach to the potential problem of climate change-related migration. One recently developed approach was a proposed Climate Change Displaced Persons Convention, which has been formulated by Hodgkinson, Burton, Anderson and Young (2010). A range of information was considered to try and find a balance between the attempt to deal with climate change as a public and foreign policy issue and the human reactions and subsequent choices people make in dealing with the effects of climate change. Due to the complications of holding a position as a public servant working in the field of responses to climate change, I decided to use a methodology that would enable me to remain a step removed from the process, to avoid influencing responses. The thesis reviews current literature and experiences on climate change and migration, particularly in the Pacific, identifies key issues, and assesses the potential effectiveness of the Convention in addressing the issues identified. Information sources included drawing on reports of first hand experience of climate change related migration and those living in the front line on the islands, experiences of working in the public and NGO sectors, and academic considerations of how to address climate change and migration.</p>

Research on the mechanism of how climate change affects cultivated soil organic carbon is the basis for the management of cultivated land quality in the context of climate change. Crop phenological responses to climate change have an important effect on cultivated soil organic carbon as well. However, previous research primarily focused on the independent effects of climate change or crop phenological responses on the changes in soil organic carbon, and few studies have analyzed the changes in cultivated soil organic carbon under the combined influence of both factors or quantified their contribution rates to the changes in cultivated soil organic carbon. Based on topsoil samples in 2008 and 2021, annual pre-season and mid-season climate data from 2008 to 2021, and the phenological parameters extracted from the enhanced vegetation index （EVI） time series from 2007 to 2022, a soil organic carbon predictive model was constructed using the random forest algorithm. The total change in soil organic carbon from 2008 to 2021, the change in soil organic carbon under climate change alone, and the change in soil organic carbon under the synergistic influence of climate change and crop phenological responses were simulated. Furthermore, the contributions of climate change and crop phenological responses to the changes in cultivated soil organic carbon were distinguished and quantified. Moreover, the dominant influencing factors of soil organic carbon changes and their spatial distributions were identified and analyzed. The results were as follows： ① Under the synergistic influence of climate change and crop phenological responses, a decrease was observed in soil organic carbon in 74.15% of the cultivated land area in Fujian Province during the years 2008-2021, with an average decrease of 2.20 g·kg-1. Additionally, there was an increase in soil organic carbon in 25.85% of the cultivated area, with an average increase of 1.48 g·kg-1. ②The average contribution rates of pre-season climate, crop phenological responses to climate change, mid-season climate, and phenological changes resulting from cultivars shifts or other adjustments of agricultural measures to soil organic carbon changes were 34.08%, 28.56%, 22.75%, and 14.61%, respectively. Overall, climate change had a greater impact on the changes in cultivated soil organic carbon in Fujian Province than the crop phenological response to climate change. ③ The regions where climate change and phenological response jointly acted as dominant influencing factors held the largest area, accounting for 47.06% of the total cultivated land area in Fujian Province, and the regions where climate change was the dominant influencing factor alone held the second-largest area, accounting for 28.64% of the total cultivated land area. ④ Higher contribution rates of pre-season climate factors and phenological changes resulting from cultivar shifts or other adjustments of agricultural measures tended to be distributed in higher-altitude areas, whereas higher contribution rates of mid-season climate factors and phenological responses to climate change tended to be distributed in lower-altitude areas. These research findings can provide a theoretical basis for decision making regarding the management of cultivated land quality and the safeguarding of food security in the context of climate change.

Climate change effects on trematodiases, with emphasis on zoonotic fascioliasis and schistosomiasis

Last winter, the United States emerged from the fourth-warmest winter on record. Farmers across the Midwest and elsewhere readied their tractors, equipment, and seeds for planting in an unusually early spring. With less snowmelt, the soil was drier than usual, and a long-term drought in the southern states of New Mexico, Texas, and Louisiana expanded to cover much of the rest of the country. By June, the drought covered 56% of the continental United States, when a heat wave hit and promised to dry the soil even further. The drought had a significant impact on agriculture and continued to worsen into July and August—critical times for crop development. By September, the USDA had designated more than 2,000 counties as disaster areas, with more than 80% of farmland impacted by the drought. It was more extensive than any drought recorded since the 1950s. If you drove through the Corn Belt in July, you may have thought you were in Hawaii gazing at plantations of spiny pineapples rather than a field of Minnesota or Iowa corn. Instead of being greeted by walls of the usual tall, green plants, you would have surveyed short, browning plants with curled leaves—symptoms of the persistent lack of water. Images courtesy of (top to bottom): Neil Palmer (CIAT), USDA-NRCS, and USDA-NRCS At the epicenter of the drought, corn and soybeans in the Midwest were hit the hardest. At the end of the season, corn yields were 122 bu/ac—the lowest since 1995, while soybeans reached only 39 bu—a level not seen since 2003. Commodity prices rose, as did the costs to consumers for many foods, especially meat, which is very dependent on grains for feed. Exports decreased as the nation prepared to import more food to meet the demand. In recent history, a number of extreme weather events have placed pressure on food supplies around the world. Australia saw a 12-year drought from 1995–2007, and in 2009, India experienced its worst drought since the 1970s. Disasters in the form of droughts and cyclones led in part to the world food crisis in 2008, which saw food shortages, price hikes, and even riots in several countries. In March last year, the Intergovernmental Panel on Climate Change (IPCC) issued a report on the effects of human-driven climate change on the frequency of extreme weather events, saying that it is likely the intensity of droughts will increase in the 21st century. The group predicts that there will be decreased precipitation and increased temperatures in many parts of the world such as Europe, the Mediterranean, North and Central America, and Africa. The 2012 drought, while stressful for both plants and people alike, has reignited a discussion about how to adapt to extreme conditions, injecting itself into debates about climate change, food security, and plant genetics. The development of several drought-tolerant varieties of corn with breeding and genetic engineering has captured much attention, as have the benefits of improved farm management. What has been missing from this discussion is how genetics and farm management interact not only with environmental conditions, but also with each other. To beat the heat, it will take scientists from many disciplines working together. To grow, all plants require water, which is absorbed by the roots and evaporates from the leaves through the stomata. When a plant becomes stressed by a lack of water, it responds by closing the stomata, wilting, losing leaves (resulting in reduced leaf area), and stimulating the growth of roots to seek out more water. Not all plants respond to drought in the same way—plants that are more efficient at this and can continue to grow with limited water are said to be drought tolerant. Increasing the drought tolerance of crops through breeding and genetic engineering has been an important goal for plant breeders, and they say these efforts are beginning to pay off. DuPont Pioneer is one company that has been working on breeding for drought tolerance since the 1950s. In 2011, it released Optimum AQUAmax corn hybrids, which it says deliver a yield advantage in water-limited environments. Breeding with drought tolerance in mind is a carefully controlled process, explains ASA, CSSA, and SSSA member Jeremy Groeteke, a Pioneer agronomy research manager in the West and member of the Optimum AQUAmax go-to-market team. Pioneer grows its corn varieties at dry locations such as Woodland, CA and Plainview, TX and controls how much water the plants receive with drip tape. Combined with whole-genome selection and 50 years of pedigree knowledge, they are able to make advances on what is a very complex trait. “You need to make sure that when you are selecting whole genomes, they interact with the key environment,” Groeteke says. Growers may encounter drought stress at critical times during development such as flowering and the grain-filling period, so they use the drip tape to time the watering to mimic those different environments. They select the best performing plants under these different conditions, while also ensuring that they perform well under normal conditions. The result, Groeteke reports, is that Optimum AQUAmax hybrids can yield up to 9% more under water-limited conditions compared with competitive hybrids. For some of the targeted farmlands, he says, this can mean 9 bu/ac more. “When we think about trying to solve global problems, adding 9 bu/ac can be pretty significant.” Monsanto has its own drought tolerance breeding program and has developed a transgenic approach that augments the results from breeding. The company has been working on an RNA chaperone discovered in Bacillus bacteria that were exposed to cold temperatures, called cspB (cold shock protein B). This protein helps the cells correct misshapen RNA molecules affected by adverse conditions and restores them to their proper functions. When tested in plants, it increased their ability to withstand stressful environmental conditions such as cold, heat, and drought. Monsanto transferred the gene that produces this protein into corn, and the company reports that its DroughtGard hybrids that incorporate this gene can yield as much as 10 bu/ac more than competing varieties under moderate drought, according to a trial conducted in 2012 across 250 farms. Monsanto expects to release these varieties this year. Images courtesy of (top to bottom): Hari Upadhyaya (ICRISAT), Tom Campbell (Purdue Agricultural Communications), and USDA-NRCS Genetics provide one way to improve the performance of crops during a drought, but plants still need water to grow. Changes in farm management practices can help increase the amount of water available to the plants and represent another important piece of the puzzle. Certain management practices can increase the water-holding capacity of the soil, while others can lower how much water evaporates into the air—leaving more to be transported into the plant. Jerry Hatfield is a Fellow of ASA, CSSA, and SSSA; lab director of the National Laboratory for Agriculture and the Environment with the USDA; and a collaborating professor at Iowa State University. He is also a member of the committee to evaluate the impacts of extreme climate events for the IPCC as well as a convening lead author for a report on the effects of climate change on agriculture for the U.S. Climate Change Science Program. One of the issues that he focuses on is how soil management practices can affect the water use efficiency of crops. “In the Great Plains, you may only get 15 to 20 inches of rainfall in a season, so getting an inch or two more stored in the soil can make a great difference,” Hatfield says. To get the soil to absorb more water, you can increase the carbon content and the biological activity in the soil. Adding manure or rotating with cover crops can increase the carbon, which also supports biological activity. This activity produces substances that affect the way the soil particles aggregate, or stick together. “If you want to start building organic matter in soil,” he says, “get continuous cover on the soil throughout the year.” Tilling also disturbs the soil, reducing carbon levels as well as biological activity, so farmers who adopt no-till practices can increase these beneficial soil components as well. Preventing evaporation from the soil can be very important when drought conditions hit. Hatfield points out that the low humidity and high temperatures during the 2012 drought made the water situation worse. “The atmosphere was pulling on the water more than it typically does.” A solution to this problem is leaving part of the previous crop on the ground. “Leaving crop residues on the soil can protect the soil surface,” Hatfield says. The residues lower the temperature of the soil surface and slow the evaporation rate. It can also help with the absorption of water. With the potential for more variation in weather patterns from year to year due to climate change, it makes management decisions more difficult. What works for a crop in a wet year such as 2010 may not work in a dry year such as 2012. But some management decisions can help mitigate both kinds of extremes. “In dry years, no-till can help the soil absorb and retain more moisture, while in wet years, it helps maintain more stable soil aggregates and protects against the harmful effects of water logging,” Hatfield says. There are trade-offs with each management strategy. While no-till and residue management can be good for drought conditions, they can also have drawbacks. Lowering the soil temperature in the spring can slow the growth of seedlings, negating the beneficial effects. “Neither full tillage or no-tillage can be pinned down as a best management practice in all environments,” Groeteke says. “Growers must manage for their local environments.” The performance of a plant depends on its genetic potential and the environment that it grows in. It would be an easy task to improve agricultural production if you only had to add the effects of these factors together, but nature does not work that way. Often, one variety will grow well in one environment, but relatively poorly in another. This interaction between the genotype and the environment is known as G × E (“G by E”). Matthew Reynolds, an ASA Fellow and CSSA member, is a principal scientist and head of wheat physiology at the International Center for Maize and Wheat Improvement (CIMMYT) in El Batan, Mexico. A main focus of his research is on adapting wheat to heat and drought stress, and he has edited a book entitled Climate Change and Crop Production. His work, like others at CIMMYT, has a global focus, breeding varieties that will grow well when the weather is good but still grow relatively well when conditions are bad. That means studying G × E. Reynolds compares the complexities of these interacting variables to designing a general-purpose car for all conditions. “In the United States, you have really good highways, some side roads, and some farmers who are driving around on dirt, which can be muddy. You can't have the perfect system for all environments, so the challenge for the breeder is to find those characteristics which are good for all—and there are a few—and to take the average bet for the rest of them. We call that broad adaptation.” Similar to how some vehicles can be switched between two- and four-wheel drive, Reynolds says “the dream is to find traits that are adaptive and switch themselves on or off when needed.” A plant that can grow deeper roots when water is scarce but not invest the extra energy when water is plentiful he says is one kind of adaptive trait that would be ideal. Reynolds and his colleagues at CIMMYT not only have to consider how different genotypes will grow in favorable and stressed environmental conditions, but also the different ways the crops will be grown. Just as individual varieties can be affected by the weather, they can also fare unequally under different management schemes. For instance, if you have a deep-rooted genotype that performs well under drought, it may not be able to grow through the hard layer formed in soils under constant cultivation. And while some crop rotations can break up disease cycles, other diseases like Fusarium can transfer from corn to wheat in the following season. A variety that is not bred specifically for a certain farming system may not realize its full potential when it is put to use. Images courtesy of (top to bottom): Detlef W. Schmalow (BASF), David Kosling (USDA), and USDA-NRCS. Both environmental conditions and management decisions are considered part of the environment that a plant interacts with. But for scientists like Hatfield and Reynolds, it can be useful to separate the outside environmental factors and the management decisions of farmers into two separate parts, E and M. “The reason you would separate management is because it is the part you control. Temperature and weather and rainfall are things that we don't control,” Reynolds explains. This approach can lead to considering how all three variables interact with each other, dubbed the “G × E × M.” Groeteke, for instance, has observed interactions between genotypes and management practices while comparing Optimum AQUAmax hybrids with competitive varieties in an extensive series of Grower Systems Trials. He shared this information at the 2012 ASA, CSSA, and SSSA Annual Meetings in Cincinnati, OH, noting that there were many management factors that can affect performance under drought for different genotypes. In particular, his team found that growers received the most yield benefit when they optimized their seeds per acre for their environment. Both Pioneer and Monsanto recommend a set of best growing practices for their drought-tolerant varieties. But since best growing practices are traditionally determined later in the breeding process, it may be possible that some ideal combinations are missed or achieved more slowly. In the book Crop Physiology: Applications for Genetic Improvement and Agronomy, Carlos Messina et al. write, “An open question is whether enhanced rates of crop improvement can be realized by a more integrated approach.” By bringing the expected environments and important future management options back to the breeding stage, genotypes that are better suited to evolving future needs like drought, heat, and diseases, can be found. “I don't know if we've spent enough time studying whether the genotypes do better under different systems,” Hatfield admits. “We've really not screened genetic material for its response to management practices. If we really want to crack this puzzle, I think we need to start thinking about what the genotypic response is to some of these factors.” Testing every genotype with every possible management scheme in every environment would be an insurmountable task. But Hatfield suggests that crop scientists and breeders can start by looking at the different components of yield. In corn, he says, “the number of rows, kernels per row, kernels per ear, and weight per kernel each represent the different stages of development. We need to start dissecting the plant to find out which are affected most by the management practices that they are subjected to.” Reynolds adds, “It's the subtlety of it. You're getting down to small effects that are hard to quantify. It is hard to come up with a genetic basis.” Quantifying effects in varied environments and systems, he says, will require an improvement in how we look at phenotypes on a mass scale—an issue he has been vocal about. “We need to be thinking about the fact that if we are to make use of the gene revolution, we are going to need much more precise phenotypic data. To capture that, we need to be able to turn those environments into a laboratory. It's a compromise—going that extra distance without losing scientific rigor, while embracing the diversity that we're trying to adapt to.” The author would like to thank Dr. Jose Crossa at CIMMYT and German Muttoni at the University of Wisconsin–Madison for their input.

Sensitivity and attribution analysis based on the Budyko hypothesis for streamflow change in the Baiyangdian catchment, China

Nutrient inputs from the atmosphere and rivers to the ocean are increased substantially by human activities. These increasing inputs of nutrients from human activities promote oceanic NPP, potentially partially counteracting decreases caused by climate change. Then, increases in export of organic matter to the ocean interior and its decomposition consumes dissolved oxygen. Therefore, nutrient inputs to the ocean promote carbon uptake and amplify climate-driven ocean deoxygenation. However, the previous generation of Earth system models that participated in the Coupled Model Intercomparison Project Phase 5 (CMIP5), which contributed substantially to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, did not account for anthropogenic nutrient inputs to the ocean. Several CMIP phase 6 (CMIP6) Earth system models do consider anthropogenic nutrient inputs to the ocean for the historical period, but their impact on ocean biogeochemical cycles has not been fully assessed, even for individual Earth system models. Therefore, our understanding of the impact of such perturbations on ocean biogeochemistry is even less complete than that associated with climate change. In particular, the quantitative relationship between the effects of climate change on ocean biogeochemical cycles and those of anthropogenic nutrient inputs remains poorly understood.In this study, using historical simulations by one of the CMIP6 models (MIROC-ES2L) that considers anthropogenic nutrient inputs, we demonstrate that the contribution of anthropogenic nutrient inputs to past changes in global oceanic productivity, carbon uptake, and deoxygenation is of similar magnitude to the effect of climate change. In particular, two noteworthy results are obtained: (1) that anthropogenic fertilization could more than counteract the expected decrease in NPP caused by ocean warming and stratification for the historical period, and (2) that it could accelerate climate-driven deoxygenation in the upper ocean, helping to close the gap between models and observations. Additionally, current estimation of the imbalance in the carbon budget could be explained partially by increase in oceanic carbon uptake associated with anthropogenic nutrient inputs to the ocean. These improvements provide support regarding the significant contribution of anthropogenic nutrient inputs to global changes in ocean biogeochemistry. Considering the effects of both nutrient inputs and climate change is crucial in assessing anthropogenic impacts on ocean biogeochemistry.

Evaluating the joint effects of climate and land use change on runoff and pollutant loading in a rapidly developing watershed