Adaptation to climate change – types and improvement. Crop simulation models in developing adaptation strategies

Climate change adaptation refers adjustment to natural or human system in response to actual or expected climate change including increase in frequency or severity of weather related disasters

Adaptation to climate change seeks to reduce the vulnerability of social and biological systems to relatively sudden change and thus offset the effects of global warming. Even if emissions are stabilized relatively soon, global warming and its effects should last many years, and adaptation would be necessary to the resulting changes in climate. Adaptation is especially important in developing countries since those countries are predicted to bear the brunt of the effects of global warming. That is, the capacity and potential for humans to adapt (called adaptive capacity) is unevenly distributed across different regions and populations, and developing countries generally have less capacity to adapt. Furthermore, the degree of adaptation correlates to the situational focus on environmental issues. Therefore, adaptation requires the situational assessment of sensitivity and vulnerability to environmental impacts.

Adaptive capacity is closely linked to social and economic development according to the IPCC. The economic costs of adaptation to climate change are likely to cost billions of dollars annually for the next several decades.

Developing countries are the least able to adapt to climate change. Doing so depends on such factors as wealth, technology, education, infrastructure, access to resources, management capabilities, acceptance of the existence of climate change and the consequent need for action, and sociopolitical will.

The IPCC group also pointed out that climate change adaptation measures can reinforce and be reinforced by efforts to promote sustainable development and reduce poverty.

Integration with development aid

Principles for effective policy

Adaptive policy can occur at the global, national, or local scale, with outcomes dependent on the political will in that area. 

The IPCC points out that many adverse effects of climate change are not changes in the average conditions, but changes in the variation or the extremes of conditions. For example, the average sea level in a port might not be as important as the height of water during a storm surge (which causes flooding); the average rainfall in an area might not be as important as how frequent and severe droughts and extreme precipitation events become. Additionally, effective adaptive policy can be difficult to implement because policymakers are rewarded more for enacting short-term change, rather than long-term planning. Since the impacts of climate change are generally not seen in the short-term, this means that policymakers have less incentive to act upon those potential outcomes. Furthermore, these problems (both the causes and effects of climate change) are occurring on a global scale, which has caused the United Nations to lead global policy efforts such as the Kyoto Protocol and Paris Agreement, in addition to creating a body of research through the IPCC, in order to create a global framework for adapting to and combatting climate change. However, the vast majority of climate change adaptation and mitigation policies are being implemented on a more local scale due to the fact that different regions must adapt differently to climate change and because national and global policies are often more challenging to enact.

Differing time scales

Adaptation can either occur in anticipation of change (anticipatory adaptation), or be a response to those changes (reactive adaptation). Most adaptation being implemented at present is responding to current climate trends and variability, for example increased use of artificial snow-making in the European Alps. Some adaptation measures, however, are anticipating future climate change, such as the construction of the Confederation Bridge in Canada at a higher elevation to take into account the effect of future sea-level rise on ship clearance under the bridge.

Much adaptation takes place in relation to short-term climate variability, however this may cause maladaptation to longer-term climatic trends. For example, the expansion of irrigation in Egypt into the Western Sinai desert due to a period of higher river flows is a maladaptation when viewed in relation to the longer term projections of drying in the region. Adaptations at one scale can also create externalities at another by reducing the adaptive capacity of other actors. This is often the case when broad assessments of the costs and benefits of adaptation are examined at smaller scales and it is possible to see that whilst the adaptation may benefit some actors, it has a negative effect on others.

Traditional coping strategies

People have always adapted to climatic changes and some community coping strategies already exist, for example changing sowing times or adopting new water-saving techniques. Traditional knowledge and coping strategies must be maintained and strengthened, otherwise adaptive capacity may be weakened as local knowledge of the environment is lost.

Strengthening local techniques and building upon them also makes it more likely that adaptation strategies will be adopted, as it creates more community ownership and involvement in the process. In many cases however this will not be enough to adapt to new conditions which are outside the range of those previously experienced, and new techniques will be needed. The incremental adaptations which were being implemented are now insufficient as the vulnerabilities and risks of climate change have increased, this causes a need for transformational adaptations which are much larger and costlier. Current development efforts are increasingly focusing on community-based climate change adaptation, seeking to enhance local knowledge, participation and ownership of adaptation strategies.

Methods of adaptation

Local adaptation efforts

Cities, states, and provinces often have considerable responsibility in land use planning, public health, and disaster management. Some have begun to take steps to adapt to threats intensified by climate change, such as flooding, bushfires, heatwaves, and rising sea levels.

Projects include:

·         Installing protective and/ or resilient technologies and materials in properties that are prone to flooding

·         Changing to heat tolerant tree varieties (Chicago)

·         Rainwater storage to deal with more frequent flooding rainfall – Changing to water permeable pavements, adding water-buffering vegetation, adding underground storage tanks, subsidizing household rain barrels (Chicago)

·         Reducing paved areas to deal with rainwater and heat (Chicago, Seoul)

·         Adding green roofs to deal with rainwater and heat (Chicago)

·         Adding air conditioning in public schools (Chicago)

·         Requiring waterfront properties to have higher foundations (Chula Vista, California)

·         Raising pumps at wastewater treatment plants (New York City)

·         Surveying local vulnerabilities, raising public awareness, and making climate change-specific planning tools like future flood maps (Seattle, Chicago, Norfolk, many others)

·         Incentivizing lighter-colored roofs to reduce the heat island effect (Chula Vista, California)

·         Installing devices to prevent seawater from backflowing into storm drains (San Francisco)

·         Installing better flood defenses, such as sea walls and increased pumping capacity (Miami Beach)

·         Buying out homeowners in flood-prone areas (New Jersey)

·         Raising street level to prevent flooding (Miami Beach)

Dealing with more frequent drenching rains may required increasing the capacity of stormwater systems, and separating stormwater from blackwater, so that overflows in peak periods do not contaminate rivers. One example is the SMART Tunnelin Kuala Lumpur.

Gardeners can help to reduce the effects of climate change by providing habitats for the most threatened species, and/or saving water by changing gardens to use plants which require less.

New York City produced a comprehensive report for its Rebuilding and Resiliency initiative after Hurricane Sandy. Its efforts include not only making buildings less prone flooding, but taking steps to reduce the future recurrence of specific problems encountered during and after the storm: weeks-long fuel shortages even in unaffected areas due to legal and transportation problems, flooded health care facilities, insurance premium increases, damage to electricity and steam generation in addition to distribution networks, and flooding of subway and roadway tunnels.

Enhancing adaptive capacity

Those societies that can respond to change quickly and successfully have a high adaptive capacity. High adaptive capacity does not necessarily translate into successful adaptation. For example, the adaptive capacity in Western Europe is high, and the risks of warmer winters increasing the range of livestock diseases was well documented, but many parts of Europe were still badly affected by outbreaks of the Bluetongue virus in livestock in 2007.

Adaptive capacity is the ability of a system (human, natural or managed) to adjust to climate change (including climate variability and extremes) to moderate potential damages, to take advantage of opportunities, or to cope with consequences. Unmitigated climate change (i.e., future climate change without efforts to limit greenhouse gas emissions) would, in the long term, be likely to exceed the capacity of natural, managed and human systems to adapt.

It has been found that enhanced adaptive capacity would reduce vulnerability to climate change. Activities that enhance adaptive capacity are essentially equivalent to activities that promote sustainable development.

Certain forms of gender inequity should be addressed at the same time; for example women may have participation in decision-making, or be constrained by lower levels of education.

Agricultural production

Adaptive ideas include:

·         Taking advantage of global transportation systems to delivering surplus food to where it is needed (though this does not help subsistence farmers unless aid is given).

·         Developing crop varieties with greater drought tolerance.

·         Rainwater storage. For example, according to the International Water Management Institute, using small planting basins to 'harvest' water in Zimbabwe has been shown to boost maize yields, whether rainfall is abundant or scarce. And in Niger, they have led to three or fourfold increases in millet yields.

·         Falling back from crops to wild edible fruits, roots and leaves. Promoting the growth of forests can provide these backup food supplies, and also provide watershed conservation, carbon sequestration, and aesthetic value.

More spending on irrigation

The demand for water for irrigation is projected to rise in a warmer climate, bringing increased competition between agriculture—already the largest consumer of water resources in semi-arid regions—and urban as well as industrial users. Falling water tables and the resulting increase in the energy needed to pump water will make the practice of irrigation more expensive, particularly when with drier conditions more water will be required per acre. Other strategies will be needed to make the most efficient use of water resources.

For example, the International Water Management Institute has suggested five strategies that could help Asia feed its growing population in light of climate change. These are:

·         Modernising existing irrigation schemes to suit modern methods of farming

·         Supporting farmers' efforts to find their own water supplies, by tapping into groundwater in a sustainable way

·         Looking beyond conventional "Participatory Irrigation Management" schemes, by engaging the private sector

·         Expanding capacity and knowledge

·         Investing outside the irrigation sector

Weather control

Russian and American scientists have in the past tried to control the weather, for example by seeding clouds with chemicals to try to produce rain when and where it is needed. A new method being developed involves replicating the urban heat island effect, where cities are slightly hotter than the countryside because they are darker and absorb more heat. This creates 28% more rain 20–40 miles downwind from cities compared to upwind. On the timescale of several decades, new weather control techniques may become feasible which would allow control of extreme weather such as hurricanes.

Damming glacial lakes

Glacial lake outburst floods may become a bigger concern due to the retreat of glaciers, leaving behind numerous lakes that are impounded by often weak terminal moraine dams. In the past, the sudden failure of these dams has resulted in localized property damage, injury and deaths. Glacial lakes in danger of bursting can have their moraines replaced with concrete dams (which may also provide hydroelectric power).

Geoengineering

Geoengineering as a "deliberate large-scale intervention in the Earth's climate system, in order to moderate global warming"

·         Solar radiation management may be seen as an adaptation to global warming. Techniques such as space sunshade, creating stratospheric sulfur aerosols and painting roofing and paving materials white all fall into this category.

·         Hydrological geoengineering - typically seeking to preserve sea ice or adjust thermohaline circulation by using methods such as diverting rivers to keep warm water away from sea ice, or tethering icebergs to prevent them drifting into warmer waters and melting. Though this is an adaptation technique, if it prevents Arctic methane release it would also be classified as mitigation.

Migration

Migration frequently requires would-be migrants to have access to social and financial capital, such as support networks in the chosen destination, and the funds or physical resources to be able to move. It is frequently the last adaptive response households will take when confronted with environmental factors that threaten their livelihoods, and mostly resorted to when other mechanisms to cope have proven unsuccessful.

It is widely accepted that the results of migration events are multi-causal, with the environment being just a factor amongst many. While many migration events can be attributed to sudden environmental change, most migration events are a result of long term environmental changes and do not cause sudden migration. 

Migration as tool for climate change adaptation is projected to be a more pressing issue in the decade to come. It is often framed in terms of human rights issues and national security. Migration events are often seen as a failure of the governments or policy making bodies that could not contain or effectively manage environmental changes. For example, extreme drought events in the Caribbean proliferate movement of peoples because of the lack of water. This is often seen as a failure on the local governments to provide structural and independent resources.

Insurance

Insurance spreads the financial impact of flooding and other extreme weather events. Although it can be preferable to take a proactive approach to eliminate the cause of the risk, reactive post-harm compensation can be used as a last resort. Access to reinsurance may be a form of increasing the resiliency of cities. Where there are failures in the private insurance market, the public sector can subsidize premiums. A study identified key equity issues for policy considerations:

·         transferring risk to the public purse does not reduce overall risk

·         governments can spread the cost of losses across time rather than space

·         governments can force home-owners in low risk areas to cross-subsidize the insurance premiums of those in high risk areas

·         cross-subsidization is increasingly difficult for private sector insurers operating in a competitive market

·         governments can tax people to pay for tomorrow's disaster

Government-subsidized insurance, such as the U.S. National Flood Insurance Program, is criticized for providing a perverse incentive to develop properties in hazardous areas, thereby increasing overall risk. It is also suggested that insurance can undermine other efforts to increase adaptation, for instance through property level protection and resilience. This behavioral effect may be countered with appropriate land-use policies that limit new construction where current or future climate risks are perceived and/or encourage the adoption of resilient building codes to mitigate potential damages.

Adaptation measures by region

The Netherlands, along with the Philippines and Japan and United Nations Environment, launched the Global Centre of Excellence on Climate Adaptation in 2017.

The countries, including Australia, have held inquiries into and have planned or started adaptation measures.

United States

The state of California has also issued a document titled "2009 California Climate Adaptation Strategy Discussion Draft" that summarizes the best known science on climate change impacts in seven specific sectors and provides recommendations on how to manage against those threats.

Poorer communities have gotten help with climate adaptation in places like Bangladesh as well. The Commonwealth of Massachusetts has issued grants to coastal cities and towns for adaptation activities such as fortification against flooding and preventing coastal erosion.

New York State is requiring climate change be taken into account in certain infrastructure permitting, zoning, and open space programs; and is mapping sea level rise along its coast. After Hurricane Sandy, New York and New Jersey accelerated voluntary government buy-back of homes in flood-prone areas. New York City announced in 2013 it planned to spend between $10 and $20 billion on local flood protection, reduction of the heat island effect with reflective and green roofs, flood-hardening of hospitals and public housing, resiliency in food supply, and beach enhancement; rezoned to allow private property owners to move critical features to upper stories; and required electrical utilities to harden infrastructure against flooding. Study of a large storm barrierspanning the entire harbor was previously proposed by the Governor of New York, but was dismissed in the City's plans.

Germany

In 2008, the German Federal Cabinet adopted the 'German Strategy for Adaptation to Climate Change' that sets out a framework for adaptation in Germany. Priorities are to collaborate with the Federal States of Germany in assessing the risks of climate change, identifying action areas and defining appropriate goals and measures. In 2011, the Federal Cabinet adopted the 'Adaptation Action Plan' that is accompanied by other items such as research programs, adaptation assessments and systematic observations.

Bangladesh

In 2018, the New York WILD film festival gave the "Best Short Film" award to a 12-minute documentary, titled Adaptation Bangladesh: Sea Level Rise. The film explores the way in which Bangladeshi farmers are preventing their farms from flooding by building floating gardens made of water hyacinth and bamboo.

India

An Ice Stupa designed by Sonam Wangchuk brings glacial water to farmers in the Himalayan Desert of Ladakh, India.

Mesoamerica

In Mesoamerica today, climate change is one of the main threats to rural Central American farmers, as the region is plagued with frequent droughts, cyclones and the El Niño- Southern-Oscillation. Although there is a wide variety of adaption strategies, these can vary dramatically from country to country. Many of the adjustments that have been made are primarily agricultural or related to water supply. Some of these adaptive strategies include restoration of degraded lands, rearrangement of land uses across territories, livelihood diversification, changes to sowing dates or water harvest, and even migration. The lack of available resources in Mesoamerica continues to pose as a barrier to more substantial adaptations, so the changes made today are much more incremental.

Nepal

In 2010, the Government of Nepal approved National Adaptation Programme of Action (NAPA). NAPA developed as a requirement under the UNFCCC to access funding for the most urgent and immediate adaptation needs from the Least Developed Countries Fund (LDCF).

In Nepal, NAPA developed with three components: Preparation and dissemination of NAPA documents, development and maintenance of the Nepal Climate Change Knowledge Management Centre (NCCKMC), and development of the Multi-Stakeholder Climate Change Initiative Coordination Committee (MCCICC).

In NAPA, nine integrated projects have been identified as the urgent and immediate national adaptation priority. They are:

1.  Promoting community-based adaptation through integrated management of agriculture, water, forest and biodiversity sector

2.  Building and enhancing adaptive capacity of vulnerable communities through improved system and access to services related to agriculture development

3.  Community-based disaster management for facilitating climate adaptation

4.  GLOF Monitoring and disaster risk reduction and forest and ecosystem management for supporting climate-led adaptation innovations

5.  Adapting to climate challenges in public health and ecosystem management for climate adaptation

6.  Empowering vulnerable communities through sustainable management of water resource and clean energy support and promoting climate smart urban settlement

NAPA’s implementation framework envisages that the operating costs will be kept to a minimum and at least 80% of the available financial resources will reach the local level to fund activities on the ground. Stakeholders in Nepal has also started discussing National Adaptation Plans(NAPs), which are medium and long term adaptation plans for the country as decided by UNFCCC

Opposition to adaptation

It is viewed that adaptation is Kind of laziness, an arrogant faith in our ability to react in time to save our skins (b)oth mitigation and adaption are necessary at this point. But for every day mitigation is delayed, the need for adaptation grows," which is problematic because "adaptation is more expensive and requires bigger government than mitigation."

Conflict-sensitive adaptation

A book by the Berliner Wissenschafts-Verlag on 'conflict-sensitive adaptation' sheds light on unintended damaging effects of climate adaptation measures. For example, when disadvantaged groups are left out of the planning process, adaptation methods such as agricultural or water programmes may increase vulnerabilities.

Crop modeling

 

the target trait (e.g., yield or resistance to drought) could be detected by QTL mapping. In this situation, the ecophysiological model is like a gene network linking all of the relevant genes into a complete picture. Some QTLs may have a small effect statistically, but that does not mean the QTL is unimportant to the target trait, even though we neglect these QTLs in almost all circumstances and turn to others that can explain more variance. When we examine the underlying traits (leaf elongation rate, leaf angle, biomass allocation, etc.) one by one, more QTLs might be discovered. Second, because of GEI, some QTLs identified as beneficial to the desired trait might have the opposite effect in another environment. Third, under the influence of pleiotropy, selecting for one trait may cause an adverse effect if that trait is

 

 

Crop modeling for climate change impact and adaptation

The use of modeling to optimize management practices, assist in breeding programs, develop new crop rotations and maximize the value of seasonal climate forecasts.

The simulation outcomes should always be evaluated critically and sometimes require further ground-truthing via field experimentations for specific conditions. For example, most of the models used for climate impact studies have been successfully tested with FACE experiments of up to 550 ppm CO₂. However, some of these models, which assume a linear relationship between elevated CO₂ and crop response, have been used for scenarios with CO₂ levels above 550 ppm, but only few models have been tested with CO₂ up to 700 ppm. In an experimental field study with potatoes, the crop response from ambient to 550 ppm atmospheric CO₂ was relatively higher than the response between 550 and 680 ppm CO₂.

Elevated CO₂ leads to stomata closure, reduction of transpiration and less canopy cooling. The interaction between CO₂ and temperature is therefore important, for example it may increase pollen sterility in rice, but it is often not considered in crop models.

A reduction of yield was noticed with elevated CO₂ in combination with warming for wheat, compared with elevated CO₂ alone. A higher photosynthetic temperature optimum in wheat under elevated CO₂ was also modeled. No such interactive effects have been reported for soybean. Crop models need to be tested with such data sets of interactive effects to ensure their validity for climate change scenarios. Similarly, interaction effects of elevated CO₂ and flooded conditions, salinity or soil constraints like soil compactions, sub-soil toxicity or transient water logging are unknown, but need to be considered. Due to the interactive effects and feedbacks that emerge when climate factors are combined, experiments in which only single factors are manipulated are likely to be inadequate to fully predict the impacts of future climate change.

Furthermore, studies with elevated CO₂ and warming at very low water supply, specific rainfall patterns and a range of soil water-holding capacities have been simulated in climate impact scenarios, but these models have never been tested with experimental data with such interactions as treatments. However, the combination effect could be very different to the sum of the single effects. For example, the net primary production response of grassland to interactive global changes (increased atmospheric CO₂, temperature, rainfall and nitrogen deposition) differed greatly from simple combinations of single factor responses.

In addition, genotype by CO₂ interactions are usually ignored in simulation studies, mainly due to the lack of experimental data, but different cultivars are often used for various regions and might respond to elevated CO₂ differently. Linking crop models with the genetic underlying structure of crops might help to adapt crops to future climate change through genetic improvements (Chapter 10). Little is known about CO₂acclimatisation of crops and hence this is ignored in simulation studies.

Nitrogen is considered in most crop models. Other nutrients such as potassium and phosphorus can also become growth-limiting factors under elevated CO₂ conditions, but are usually not considered in crop models or in climate impact studies. Nutrients could also become limiting when climate change alters soil factors, for example by restricting root growth for nutrient uptake.

Quality aspects of yield are often affected by climate but are not, or are less well simulated than yield itself (e.g. protein composition, oil content), and simulation studies on the impact of climate change will require a better understanding of the physiology of yield quality and its incorporation into crop models.

Specific changes in climate could become critical in determining the impact on crops. For example, the importance of minimum temperature, rather than just mean temperature, for grain yield determination in wheat and rice needs more attention and might require modifications on how crop models respond to changes in minimum temperature. Also, if the frequency of dry winds with high VPD increases with climate change in some regions, the potential damage to crops demands further study as dry winds are ignored in current crop models.

Physiological processes such as sink–source relationships of grain yield, correctly or incorrectly represented in crop models, could be differently affected by elevated CO₂ and increased temperature. For example, wheat grain yield has been reported to be reduced under elevated CO₂ in sink-manipulated shoots, implying that a high source:sink ratio may result in a down-regulation of photosynthetic capacity that more than offsets the direct stimulating effect of elevated CO₂.

One of the challenges in climate change impact research is how to deal with extreme events like heat stress, frost and flooding. While the frequency of extreme events is often predicted to change in the future, predicting the timing of extreme events is still poor. However, the timing of critical events is crucial in determining the crop impact as the impact often depends on the crop phenological stage (e.g. frost and flowering of cereals).

Despite these many knowledge gaps, crop models that integrate crop physiological understanding with soils hydrology, soil carbon and nutrient dynamics have improved our understanding of the impacts of climate change on many aspects of local and world food production. The application of these models stimulates investigations into climate change adaptation and assists in communication with the public and policy makers that continued climate change could have a devastating impact on food supply. Continually improving crop models with further physiological understanding will help to improve our appreciation of future climate change impact and adaptation options in agriculture.

High-Temperature Effects on Rice Growth, Yield, and Grain Quality

As early as 1980s, the MACROS crop simulation model was used to study the effect of climate change on rice production at the IRRI, Philippines. Using the weather data from four contrasting sites (the Netherlands, Israel, the Philippines, and India), simulation on the average grain yield and its variability of rice under both fully irrigated and rain-fed conditions was performed. By using the MACROS crop simulation model, suggested rice yield increases of 10–15% due to a doubling of the CO₂ level, but the effect of the expected accompanying rise in temperatures would offset those increases.

Increased photosynthesis at higher CO₂ levels, and reduced length of the growing season and increased maintenance respiration rates at higher temperatures were the plausible changes in the physiological activities under elevated [CO₂] and high temperatures. Describing the relationship between yield and minimum temperature over the range 22.1–23.7 °C using a quadratic equation, Yield declined with minimum temperature by 10% per 1 °C and yield declined with average temperature by 15% per 1 °C (given the relative contributions of maximum and minimum temperatures to mean daily temperature). Much smaller yield changes with temperature ranging from about 2% to 6% per 1 °C from a base yield for the temperature range 22–32 °C were suggested by other workers. Simulation models were used to study the effect of high temperature on seed-setting rate and grain yield by combining the daily flower characteristics.

A process-based model was developed to simulate the high-temperature-induced sterility, which considered the flowering characteristics of rice and daily change of air temperature. Hypothesis that high temperature induces spikelet injury was evaluated by enhancing the tolerance level of cv. IR36 in the ORYZA1 model. Without any temperature tolerance of cultivar, large decreases in yield due to spikelet sterility were predicted.