|
PDF
Versions of:
This
Overview section
More
detailed chapter from "Foundation" report.
The
National Assessment Overview and
Foundation Reports were produced by the
National Assessment Synthesis Team, an
advisory committee chartered under the Federal Advisory Committee Act, and were not subjected to OSTP's Information Quality Act Guidelines. The
National Assessment was forwarded to the President and Congress in
November 2000 for their consideration.
It is vital to our national interest that we meet these research
needs so that we can, with increasing certainty, address the critical
question: How vulnerable or resilient are the nation's natural and human
resources and systems to the changes in climate projected to occur over
the decades ahead?
An integrated research approach would address such questions as:
How will the combination of high concentrations of ground-level ozone,
high heat stress, and other factors affect human and plant health,
especially in sensitive areas, such as the Great Smoky Mountains National
Park, and metropolitan Houston?
Assessment of US impacts, including potential benefits, will
increasingly require an examination of changes and response strategies
around the world, and the manner in which these are translated to the
global marketplace and environment.
The recommended research could help identify key thresholds beyond
which certain ecosystems would no longer perform services people rely
upon. For example, at what point would a particular lake no longer
provide habitat for certain types of fish dues to changes in climate
hydrology, and excess nutrient input from fertilizer runoff?
The recommended ecosystem research could address such questions as:
• How will climate change
combine with increased demand for agricultural production and increased
urbanization of affect the rate of species endangerment in the US?
• Will climate change and thee
increase in atmospheric CO2 stimulate carbon sequestration in US forest
ecosystems? If so, how much carbon will be sequestered and
which forests will be the most effective carbon sinks.
To assess real impacts on people and their societies, we should
improve our understanding of how people and institutions will adapt to
change and of the factors that will determine their vulnerability.
The recommended research could help address questions such as:
•What are the likely costs of
adapting to increases in average temperature and heat index?
•To what degree can cities
take climate change into account in planning for new infrastructure, such
as water distribution and routing, bridges, and peak power demands?
Every 3 to 7 years, the US is affected by a cycle of El Nino and La
Nina events that leads to major changes in the frequency of hurricanes and
in the paths of other weather systems that are responsible for extremes of
precipitation and temperature across the US. The recommended
research will enable future assessments to project how climate change will
alter the frequency and severity of these extreme weather events.
A commitment to sustained high-quality observations is necessary for
detecting changes in important aspects of our environment. New and
improved data sets are required to address questions such as:
•How is our environment being
altered by climate change?
•How much confidence can we
place in projections, given our ability to understand past changes and
variations?
We must accept the challenge to learn more and to conduct future
assessments of multi-dimensional changes in climate, other environmental
processes, and socioeconomic conditions. Meeting this challenge will
require the new approaches, new knowledge, and new capabilities outlined
above that can help reduce uncertainties while taking advantage of the
great amount that we already know. |
|
New Approaches, New Knowledge, and New Capabilities
for Our Nation
The National Assessment has defined a new vision for climate-impacts
research. This vision has at its core a focus on integrated regional
analysis and a close partnership of natural and social scientists with
local, regional, and national stakeholders. Integrated analysis refers to
considering the full range of stresses that affect a resource or system,
including climate change and variability, land use change, air and water
pollution, and many other human and natural impacts. For example, in
studying water quality in a particular place, the direct and indirect
effects of urban development, agricultural runoff, industrial pollution,
and climate change-induced increases in heavy precipitation events all
would need to be considered, along with many other factors. Integrated
analysis also refers to integrating across all the relevant spatial scales
for an issue, and these may extend from local to regional to national and
even to global, depending on the issue. In the example of the local water
quality study, this would mean integrating the effects of large-scale
weather patterns on precipitation, as well as pollution inputs on both
large and small scales, some of which originate far from the study area.
Such integration across both multiple stresses and multiple scales is
needed to provide the type of comprehensive analysis that decision-makers
seek.
Guided by this vision, the first National Assessment has identified a
range of regional and sector vulnerabilities to climate variability and
change that call for the attention of the American people and their
leaders. In identifying vulnerabilities, the authors of the Assessment
took great care to evaluate the likelihood of various climate-related
outcomes. The likelihood of a number of outcomes was considered to be
high. However, the likelihood of some of the other important potential
outcomes was more difficult to judge due to lack of appropriate methods,
uncertainties in knowledge, or shortcomings in research infrastructure
such as computer power.
As our nation considers its strategies for dealing with climate-related
vulnerabilities, scientists must work to reduce uncertainties underlying
the vulnerability estimates. To assure that efforts to reduce
uncertainties are efficient and to the point, the authors of the
Assessment have identified a short list of priority research steps that
are outlined below. These steps are organized into three categories: New
Approaches, New Knowledge, and New Capabilities. It is vital to our
national interest that we meet these research needs so that we can, with
increasing certainty, address the critical question: How vulnerable or
resilient are the nation's natural and human resources and systems to
the changes in climate projected to occur over the decades ahead? With the
new vision of regional analysis and scientist-stakeholder partnerships
developed in the National Assessment, we have a powerful approach to
effectively address this complex question.
Recommendation 1: Develop a More
Integrated Approach to Examining Impacts and Vulnerabilities to
Multiple Stresses
Recommendation 2: Develop New
Ways to Assess the Significance of Global Change to People |
This first National Assessment experimented with new approaches for
linking the emerging findings and capabilities of the scientific community
with the real-time needs of stakeholders who manage resources, grow food,
plan communities, sustain commerce, and ensure public welfare. Teams were
established in various regions across the country to look at how climate
variability and change would affect particular locations. Other teams were
established on particular topics that focused on how climate variability
and change would affect issues of national significance. These types of
efforts need to be sustained and expanded. In doing so we can build on a
number of existing federal programs.
Recommendation 1:
Develop a More Integrated Approach to Examining Impacts and
Vulnerabilities to Multiple Stresses
The key requirement is to develop a truly integrated and widely
accessible approach at regional and national scales appropriate for the
examination of regional and national problems associated with biologic,
hydrologic, and socioeconomic systems. A number of the regional and sector
studies supporting the National Assessment have made important progress in
such efforts but substantial additional efforts are required.
Expand the national capability to develop integrated, regional
approaches of assessing impacts and vulnerabilities.
The regional teams supporting the National Assessment have produced
new and innovative partnerships among a wide variety of scientists and
stakeholders. In the process, they have catalyzed new modes of research
and have demonstrated the potential of an integrated approach to
assessing the consequences of climate variability and change. If the
nation is to have improved projections of the impacts of and
vulnerabilities to multiple stresses, we must accelerate the process of
integrating research capabilities across the spectrum of natural and
social sciences with the needs of public and private decision-makers.
The importance of multiple stresses on specific environments and the
importance of linkages between physical, biological, chemical, and human
systems, require enhanced capabilities for regional analysis.
The key elements of this strategy must be to (a) integrate
observations at a regional level; (b) develop a comprehensive system
designed to make the enormous amounts of data and information more
accessible and useful to the public; (c) enable field and experimental
studies that focus on solving regional problems; and (d) develop a
foundation for building tractable, high-resolution coupled models that
can address the outcomes associated with multiple stresses unique to
each area of the country. Regional assessments add impetus for
developing a comprehensive integrated approach, and this integration
will engender substantial new capabilities to address the relationships
between climate and air quality, energy demand, water quality and
quantity, species distribution, ecosystem character, ultraviolet
radiation, and human health indices in specific regions.
Perform integrated national investigations of additional sectors
and issues.
The choice of major sectors in this Assessment (water, forests, human
health, coastal regions, and agriculture) reflected the fact that they
were likely to be informative and important. Some of the themes were
represented by a strong foundation of methods and models (e. g.,
agriculture) while others represented capabilities at very early stages
of development (human health). These themes yielded a number of future
research needs (e.g., the need to better understand human health
relationships to extreme temperatures, other extreme weather events, and
air quality, and to better characterize the relationships between
climate and disease vectors and then between vector distribution and
disease). In addition, a large number of important sectors and themes
were not addressed, including climate impacts on transportation, energy,
urban areas, and wildlife. These will require future investment in
supporting research and assessment.
Consider international linkages in assessing national impacts.
In some cases, the vulnerability and resiliency of the US to climate
impacts are highly dependent on the nature of the changes in other
countries. For example, in the case of agriculture, the nature of the
impacts strongly depends on international markets, and therefore the
production and distribution of major crops around the world. These
markets will reflect the extent of temperature and precipitation changes
in other nations and the ability of these nations to cope with climate
change and variability. Assessment of US impacts, including potential
benefits, will increasingly require an examination of changes and
response strategies around the world, and the manner in which these are
translated to the global marketplace and environment.
Recommendation 2:
Develop New Ways to Assess the Significance of Global Change to People
New methods for examining the potential impacts of climate change,
adaptation options, and the vulnerability of communities, institutions,
and sectors are essential to improving the assessment process. Research on
these issues would result in a far greater ability to anticipate possible
surprises, incorporate socioeconomic data in our analyses, and provide
information that is useful for public and private decision-makers. The key
research requirements involve improving methods to:
Understand and assign value to large and non-market impacts
(e.g., on communities, resources, and ecosystems).
Changes that occur in natural and managed ecosystems, natural
resources, and the other sectors are important because people assign
them value, either in market or non-market terms. It is crucial to
develop new ways to assign values to possible future changes in
resources and ecosystems, especially in the cases of very large impacts
and of processes and services that do not produce marketable goods. A
focus on large impacts and non-market systems should provide insights
that would enable decision-makers to understand the potential
consequences of environmental change, as well as the potential
consequences of particular adaptation or mitigation decisions.
Represent, analyze, and report uncertainties.
Describing scientific uncertainty is a task that faces every
assessment of impacts or vulnerability. Findings in this Assessment, and
their associated uncertainties, are based on the considered judgment of
the NAST and on the peer-reviewed literature. The assessment process
should extend the capabilities of decision-makers to understand
potential uncertainties. For this reason, a range of additional methods
for representing, analyzing, and reporting uncertainties should become a
research focus.
Assess potential thresholds and breakpoints.
Some ecosystems and human institutions do not respond to rapid
changes or stresses in continuous ways; if the stress exceeds certain
thresholds, the system changes very rapidly, and sometimes in
irreversible ways. It is very important to understand these types of
responses because they raise particularly difficult challenges for
adaptation. Using climate scenarios to help determine the conditions
under which such changes might occur is therefore extremely important to
pursue, because it can provide information of direct utility to
decision-makers.
Develop and apply internally consistent socioeconomic futures for
use in assessing impacts.
In order to consider adaptation responses and ultimate
vulnerabilities to climate change and other environmental stresses,
assessments need to consider alternative possible socioeconomic and
climatic futures using scenarios, probability distributions, or other
methods. This Assessment began this process, but new methods to develop
and apply such futures will improve the quality of the evaluation of the
potential for adaptation in sector, regional and national analyses.
Recommendation 3: Improve
Projections of How Ecosystems Will Respond
Recommendation 4: Enhance
Knowledge of How Societal and Economic Systems Will Respond to a
Changing Climate and Environment
Recommendation 5: Refine our
Ability to Project How Climate Will Change |
Determining how climate change will affect us necessarily builds on a
wide array of scientific knowledge, not just of how the atmosphere works,
but of how land ecosystems, the oceans, society, and many other aspects of
the Earth system interact. Building this base of knowledge was the reason
for establishing the US Global Change Research Program, and for the many
programs and projects that it supports. Findings of this research have
been essential to the overall undertaking of the Assessment. However, in
the course of this Assessment, a number of areas have been identified
where specific types of new knowledge are needed to assist society in
preparing for the changing conditions of the 21st century. Improving
projections of the responses of ecosystems, societal and economic systems,
and climate, would improve scientists' ability to answer questions that
are important to decision-makers.
Recommendation 3:
Improve Projections of How Ecosystems Will Respond
The nature of the response of complex natural and managed ecosystems to
multiple stresses is one of the most important challenges to providing
more certain projections of the impacts of climate variability and future
climate change. Scientific studies are needed to extend our knowledge of
many types of interrelationships between climate and ecosystems. These
complex, interdependent interactions determine how organisms will respond
to climate and other stresses and determine the potential vulnerability
and/or resilience of these systems. Areas requiring intensified research
to address this challenge include:
Terrestrial and aquatic natural ecosystem responses to multiple
stresses, including the consequences for productivity, biodiversity, and
other ecosystem processes and services.
Information is lacking on local, watershed, and continental scales to
evaluate the responses of terrestrial and aquatic ecosystems to
combinations of environmental stresses. Experimentally and
observationally based investigations are needed of combinations of
important environmental changes (such as changes in: CO2 concentration;
climate variability, temperature, land use, air and water quality, and
species composition) as they affect important ecological processes
(including productivity and nutrient cycling), attributes (such as
species diversity, the responses and interactions of important
individual plant and animal species, and the interactions among plant
and animal communities), and services (such as regulating runoff).
Results from such field experiments are needed as inputs for more
sophisticated generations of ecosystem models to provide the information
needed to project the responses of ecosystems to combinations of
stresses, rather than separately treating individual stresses.
Managed ecosystem responses to multiple stresses, including their
consequences for water quality and runoff, soil fertility, agricultural
and forest productivity, and pest, weed, crop, and pathogen interactions
through the development of integrated observations, process studies, and
models.
Effective management of agricultural lands, forested ecosystems, and
watersheds is closely coupled to the influences of pests, pathogens,
climate, and other environmental variables. These interactions have not
been addressed adequately in an experimental fashion. Research is needed
on the interactions of these factors as they affect crop and forest
productivity, soil fertility, water quality and quantity, the spread of
pathogens and weeds, etc. Results from such experiments would provide
insight into potential vulnerabilities from the combinations of
environmental stresses, and input to better management responses to
changes in those stresses.
The importance and interactions of climate, land cover, and land
use in nutrient cycling, water supply and quality, runoff, and soil
fertility.
Current land use models include socioeconomic variables such as human
population size, affluence, and culture. However, the influences of
climate change on land use, and of land use changes on regional climate
are not adequately considered. Available analyses of ecological change
tend to make one of two simplifications: either that a region is covered
by its potential natural vegetation (the vegetation that would exist in
the absence of human activities) or that the land-cover and land-use
will remain as it is now, independent of climatic or other stresses.
Both of these perspectives are limiting because they simplify the
feedbacks between land use, ecological systems, and climate. New models
of land-use change that integrate actual land-cover and land use
information with ecological and economic processes would provide a
crucial context for examining the potential consequences of human
land-use decisions on a wide variety of ecosystem goods and services.
Better observations and models of ecosystem disturbance, and
species dispersal and recruitment.
The ability to project changes in the ranges of important tree and
plant species, and therefore changes in the make-up of forests and other
ecosystems, is critically limited by information about the frequency of
fires and other disturbances, the ability of seeds to disperse across
current landscapes, and the factors that determine the success of plants
in establishing themselves in new habitats and locations. Field
observations, experimental studies, and historical analyses of past
ecosystem changes are needed in order to understand both what is
possible and the distances and rates of range changes that important
species might actually achieve as climate changes. Such results would
help fill crucial gaps in knowledge and enhance our ability to project
the future ranges and distribution of important species.
Recommendation 4:
Enhance Knowledge of How Societal and Economic Systems Will Respond to a
Changing Climate and Environment
A greater understanding of the vulnerability and resilience of societal
and economic systems is essential to addressing key uncertainties. Human
roles in and responses to climate change and other environmental stresses
are among the most important features of impact assessments. To assess
real impacts on people and their societies, we should improve our
understanding of how people and institutions will adapt to change and of
the factors that will determine their vulnerability. Gaining such
knowledge will require investing in the following key areas:
Understanding the resilience of communities, institutions,
regions, and sectors (e.g., human health, urban areas, transportation,
and international linkages).
The ability of communities, institutions, regions, and sectors to
adapt has only begun to be addressed in this Assessment. Understanding
how the capacity to adapt to a changing climate might be exercised, and
therefore what vulnerabilities to climate change and other environmental
stresses might remain, is an important next step in the human dimensions
research agenda. The results of this research would enable a more
integrated evaluation of both natural and social science aspects of
human responses.
Improving understanding of how people and institutions have
adapted to past climate variability and extreme events.
There is a wealth of information available on how people and
institutions have responded to climate variability and other
environmental changes in the past. New research that documents these
responses, analyzes the underlying reasons for them, and explains how
individual and institutional decisions were actually made will provide
important insights into the feasibility of coping and adaptation options
that might be available and considered in the future.
Greater information and analysis of specific potential adaptation
options (e.g., costs, efficacy, time horizons, feasibility, and other
impacts).
One of the critical unknowns in this Assessment's consideration of
adaptation options stems from a lack of information about their
potential costs, efficacy, time horizons required for implementation,
other consequences, and feasibility. This type of information should be
gathered as decision-makers consider specific adaptation options.
Recommendation 5:
Refine our Ability to Project How
Climate Will Change
This first National Assessment has revealed a number of key
uncertainties in projecting climate change and variability at global,
national, and regional scales. These uncertainties limit our ability to
assess the responses of natural and managed ecosystems and societal and
economic systems. Of greatest significance to decision-makers will be
reducing uncertainties in several key areas by pursuing research that will
lead to:
Improved understanding and analysis of the potential for future
changes in severe weather, extreme events, and seasonal to interannual
variability.
Many of the results in this Assessment demonstrate that changes in
climate variability across a wide range of spatial and time scales have
very important impacts on ecosystems, natural resources, and human
systems. Long-term climate variations are strongly affected by how the
oceans store and transport heat from warm regions near the equator to
cold regions at high latitudes. For example, the El Niño-Southern
Oscillation (ENSO) influences extreme weather and climate events by
affecting the paths, frequency, and severity of winter and tropical
storms. While model projections of ENSO and other sources of variability
have advanced greatly over the past few years, much additional work is
needed on how human-caused climate change might affect these patterns of
variability. Much greater understanding is also needed about how climate
change will influence the frequency, intensity, and likely locations of
severe weather and climate events such as droughts, hurricanes,
tornadoes, severe thunderstorms, and meteorological events that produce
severe flooding.
Improved understanding of the spatial and temporal character of
hydrologic processes, including precipitation, soil moisture, and
runoff.
Some of the most important differences among climate model
simulations involve projections of precipitation, soil moisture, and
runoff, and these are of the greatest significance for ecosystems,
agriculture, and water quality and quantity. Despite their importance,
there is incomplete understanding of the physical processes that govern
the water cycle and the extent to which these processes will be modified
by climate change. The differences are sufficiently large in some
regions of the country that we cannot even project whether there will be
an increase or a decrease in soil moisture and runoff in these regions.
A critical element of climate research must be an improved ability to
simulate all aspects of the water cycle. Results of this research would
substantially improve the estimates of potential vulnerabilities to
climate change and other stresses.
Increased information on the nature of past climate, including
its spatial and temporal character.
Model-generated scenarios of climate change and variability are only
one way to examine potential futures. Another important method is to
reconstruct the regional record of past changes in climate and their
consequences in order to improve our understanding of how the natural
world has operated in the past. These records illustrate the nature of
past variability, provide an opportunity to assess climate model
sensitivity, and offer insights into the response of ecological systems
to past climate change. Results of this research would raise our
confidence in the application of climatic information to evaluate
impacts and vulnerability.
The nation needs a stronger capability for providing climate
information that serves the national requirements for assessing
vulnerabilities and impacts. A stronger national capability could deliver
climate projections, including increased access to reliable model outputs
and observational information, improved understanding of limitations, and
greater availability of the specialized products required by increasingly
sophisticated assessment science. Climate modeling and analysis are the
foundation for developing climate scenarios that describe alternative
futures for analysis of potential impacts of climate change, adaptation
options, and vulnerability. Several steps can be taken in the near-term to
enhance our capabilities to provide and use scenarios.
Recommendation 6:
Extend Capabilities for Providing
Climate Information
Addressing the broad spectrum of future societal needs will require
continued improvements in observations, analysis, and the ability to
forecast a wide variety of environmental variables. The elements required
to develop comprehensive capability include:
A national modeling and analysis capability designed to provide
long-term simulations, analysis of limitations and uncertainties, and
specialized products for impact studies.
The nation's climate modeling expertise is widely recognized
throughout the world and this expertise is dedicated to developing
state-of-the-science model capability. Ensembles of long-term
simulations, extending from the start of the robust historical record to
at least the next 100 years, would provide important information to the
nation. Further, the regional and sector teams in this Assessment have
been requesting a host of specialized climate products that more
directly tie future climate projections to specific decisions or
vulnerabilities. The assessment process requires greater access to and a
greater understanding of the limitations inherent in future projections
in order to weigh the advantages and risks of alternative courses of
action. Substantially higher model resolution is required to link
climate with the scales of human decisions. The demand for these climate
services exceeds the capabilities of the research functions of the
nation's climate modeling centers.
Dedicated computer capability for developing ensemble climate
scenarios, high-resolution models, and multiple emission scenarios for
impact studies.
There is a need for ensemble climate simulations based on
multiple-emission scenarios devoted to studies of climate impacts,
vulnerabilities, and responses. The investment that is needed is to
enhance the capacity of the climate modeling community to generate and
analyze model runs that are dedicated for use by impact analysts.
Similarly, future assessments need to investigate a range of plausible
emissions and atmospheric concentrations of carbon dioxide and other
greenhouse gases. The results of enhancing the capability to generate
dedicated scenarios of emissions and climate would be a dramatic
improvement in the range of outcomes that future assessments of
vulnerability could analyze.
Reliable long-term observations and data archives.
One of the most often encountered limitations to the conduct of this
Assessment, and one of the most often expressed needs of participants in
the regional and sector assessment process, has been the lack of
databases that truly reflect changes and variations in the environment,
as opposed to those that unduly reflect uncertainties in observing
methods. A commitment by the nation to provide integrated databases and
information on multiple environmental conditions and trends, and
indicators/measures of climate and related environmental changes, is
essential to support and implement the research agenda. The US has
tremendous potential to create more efficient and comprehensive
measurement, archive, and data access systems that would provide greater
scientific benefit to society by building upon existing weather and
hydrologic stations and remote sensing capability, and integrating
current efforts of local, state, and federal agencies. Improved data and
information archives will substantially enhance future assessments.
Addressing the Full Agenda
While the proposed research activities are all important individually,
it will not be possible to substantially reduce our uncertainties and gaps
in knowledge without consideration of their interconnections and
interdependencies.
The National Assessment Synthesis Team is convinced that the nation
will benefit from multi-year investments in this focused program of
research. Benefits will include major enhancement in our knowledge of the
impacts of and vulnerabilities to global change on scales appropriate to
the national interest and in our capacity to assess their importance.
We must accept the challenge to learn more and to conduct future
assessments of multi-dimensional changes in climate, other environmental
processes, and socioeconomic conditions. Meeting this challenge will
require the new approaches, new knowledge, and new capabilities outlined
above that can help reduce uncertainties while taking advantage of the
great amount that we already know. Many of the building blocks of
scientific knowledge, analytical capability, and commitment to the
required integration are now in place. Through its regional, sector, and
integrated approach, this Assessment has taken an important first step
toward that future.
Areas with High Potential for
Providing
Needed Information in the Near-Term
- Expand the national capability to develop integrated, regional
approaches of assessing the impacts of multiple stresses,
perhaps beginning with several case studies.
- Develop capability to perform large-scale (over an acre)
whole-ecosystem experiments that vary both CO2 and climate.
- Incorporate representations of actual land cover and land use
into models of ecosystem responses.
- Identify potential adaptation options and develop information
about their costs, efficacy, side effects, practicality, and
implementation.
- Develop better ways to assign values to possible future
changes in resources and ecosystems, especially for large
changes and for processes and service that do not produce
marketable goods.
- Improve climate projections by providing dedicated computer
capability for conducting ensemble climate simulations for
multiple emission scenarios.
- Focus additional attention on research and analysis of the
potential for future changes in severe weather, extreme events,
and seasonal to interannual variability.
- Improve long-term data sets of the regional patterns and
timing of past changes in climate across the US, and make these
data-sets more accessible.
- Develop a set of baseline indicators and measures of
environmental conditions that can be used to track the effects
of changes in climate.
- Develop additional methods for representing, analyzing, and
reporting scientific uncertainties related to global change.
|
|
|