The University of North Carolina at Chapel Hill Climate Change Committee Report 2009 pptx

Institute for the Environment



The University of North Carolina at Chapel Hill
Climate Change Committee Report
2009
Edited by

Larry Band, Voit Gilmore Distinguished Professor,
Department of Geography, and Director,
Institute for the Environment

David Salvesen, Deputy Director,
Center for Sustainable Community Design,

ii

Cover photos: (Clockwise from left) Hurricane Bonnie
over the North Carolina coast (photo courtesy NOAA);
Wildfire blazes in Hyde County, North Carolina, June
2008 (Photo by Chris Curry, The Virginian-Pilot);

A child enjoying the North Carolina coast; A nearly
dried-up Falls Lake in Durham County, North Carolina,
during the summer of 2007 (photo by Kevin Greene).

iii
Preface
This report addresses the significance of climate change to North Carolina. The report was
developed by a committee of faculty and staff at the University of North Carolina at Chapel Hill in
response to a specific request from the University of North Carolina General Administration (UNC-
GA) and the North Carolina State Senate. The request was transmitted to the Institute for the
Environment (IE) by Provost Bernadette Gray-Little as received from UNC-GA, and was followed
up for clarification with UNC-GA and Legislative personnel. Each campus was asked to produce a
report on global warming impacts on North Carolina independently, without inter-campus
collaboration. In this report, we emphasize the areas of research strength at Carolina without
extensively addressing areas that are better suited to other campuses. As an example, agricultural
impacts are minimally discussed, assuming North Carolina State University will provide a more
extensive treatment.

The report includes a brief review of climate change science, an assessment of climate change trends
and likely impacts on North Carolina, as well as the potential to mitigate and adapt to those impacts.
Given the short time frame to prepare the report (August – November), we were not asked to
conduct any new research, but instead to summarize and synthesize faculty and scientific community
knowledge on this significant and wide ranging issue. The report responds to the request to
incorporate faculty members’ individual and collective assessment of climate change for the state,
including statements of the degree of uncertainty and disagreement on specific impacts or potential
policy options.

We address major issues of climate change uncertainty, current trends in climate, and their
consistency with expectations of climate change models. We put the scientific understanding and
popular conception of global climate change into the perspective of North Carolina’s geography,

and discuss specific vulnerabilities to the coastal region, the mountains and the Piedmont. We
identify opportunities for the state to be proactive in working to mitigate the impacts of climate
change, while preparing an adaptive strategy to increase our resilience to expected change. We
highlight policy actions that have “co-benefits” to economic, environmental and health conditions,
even if climate change is ultimately smaller than expected.


iv
Similar efforts inside and outside North Carolina
Other states and regions in the United States have carried out detailed, long term assessments of
climate change threats and opportunities. For example, Maryland recently completed a 16 month
study ( of climate change impacts. Virginia is in the
process of conducting a similar study over a one-year time period. A consortium of northeastern
states carried out an in-depth two year study of potential climate change and vulnerability for that
region ().

In North Carolina, the Legislative Commission on Global Climate Change, established in 2005, is in
the process of developing a report with a complementary scope (particularly in the areas of
mitigation and adaptation). We reference material from that effort and note that one of our
committee members, Professor Richard Andrews, is a member of the Commission. In addition, the
North Carolina Climate Action Plan Advisory Group, established in 2006, recently released its
report which also emphasizes mitigation (reduction or avoidance) of climate change. The state
should be proactive in coordinating with neighboring states on an in-depth regional study of climate
change, while also extending the depth of its activity focused on North Carolina.
Report Development Process
The IE coordinated two meetings with faculty selected from multiple schools at UNC Chapel Hill,
including Arts and Sciences, Medicine, Law, Public Health and Government. Faculty were contacted
on the basis of their individual expertise and were asked to examine the range of significant climate
change impacts expected in North Carolina, as well as the potential for policy, management, and
technical approaches to mitigate and prepare for impacts. The faculty climate change committee

contributed substantially to the development of the report by writing and coordinating the
contributions of other faculty in their fields. We note that there are many more faculty members at
UNC Chapel Hill carrying out high quality research and service in related areas that could have
contributed to the report, but were not included given the time and resource constraints of the
process.
Report Organization
The report is organized into five chapters following the preface. Chapter 1 provides an overview of
climate change science. Chapter 2 covers environmental impacts of climate change in North

v
Carolina, including potential effects on freshwater resources, sea level and coastal water quality, air
quality, and ecosystems. Chapter 3 investigates the impacts of climate change on environmental
systems and human health. Chapter 4 concentrates on mitigation and adaptation. A number of
suggestions for policy, management and research options for North Carolina to consider are offered
in the first four chapters. Chapter 5 summarizes cross-cutting recommendations.


vi
Contributors
Pete Andrews
Thomas Willis Lambeth Distinguished
Professor of Public Policy and Chair
Department of Public Policy

Lawrence E. Band
Voit Gilmore Distinguished Professor
Department of Geography
Director
Institute for the Environment

Philip Berke
Professor
Department of City and Regional Planning
Director, Center for Sustainable Community
Design
Institute for the Environment

Phillip Bromberg
Bonner Professor of Medicine
Scientific Director,
Center for Environmental Medicine, Asthma
and Lung Biology
School of Medicine

Jeffery Brubaker
Graduate Student
Department of City and Regional Planning

Raymond Burby
Professor Emeritus
Department of City and Regional Planning

Gregory W. Characklis
Associate Professor
Department of Environmental Sciences &
Engineering

Martin Doyle
Associate Professor
Department of Geography

Director, Center for Landscape Change and
Health
Institute for the Environment



David R. Godschalk
Professor Emeritus
Department of City and Regional Planning

Bernadette Gray-Little
Executive Vice Chancellor and Provost
Office of the Executive Vice Chancellor and
Provost

Donald T. Hornstein
Aubrey L. Brooks Professor of Law
School of Law

Chip Konrad
Associate Professor
Department of Geography
Deputy Director, NOAA Southeast Regional
Climate Center

Hillel S. Koren
Health Scientist
Human Studies Facility, U.S. Environmental
Protection Agency

Rick Luettich
Professor
Department of Marine Sciences and Institute of
Marine Sciences
Director, Institute of Marine Sciences

Jacqueline MacDonald
Assistant Professor
Department of Environmental Sciences &
Engineering

Brent McKee
Mary and Watts Hill, Jr. Distinguished Professor
and Chair
Department of Marine Sciences

David McNelis
Research Professor, Environmental Sciences
and Engineering and
Director, Center for Sustainable Energy,
Environment and Economic Development
Institute for the Environment


vii
Charles Mitchell
Assistant Professor
Biology

Rachel Noble

Associate Professor
Department of Marine Sciences
Director, Morehead City Field Site
Institute for the Environment

Hans Paerl
William R. Kenan Professor
Department of Marine Sciences and Institute of
Marine Sciences

David Peden
Professor of Pediatrics and Medicine
Director, Center for Environmental Medicine,
Asthma and Lung Biology
School of Medicine

Bob Peet
Professor
Department of Biology

Mike Piehler
Assistant Professor
Department of Marine Sciences

Robert K. Pinschmidt, Jr.
Deputy Director
Institute for Advanced Materials, Nanoscience,
and Technology

Jose Rial

Professor
Department of Geological Sciences

Justin Ries
Assistant Professor
Department of Marine Sciences

Peter Robinson
Professor
Department of Geography
Director
NOAA Southeast Regional Climate Center

Daniel Rodriguez
Associate Professor
Department of City and Regional Planning

Tony Rodriguez
Associate Professor
Department of Marine Sciences

David Salvesen
Deputy Director
Center for Sustainable Community Design
Institute for the Environment

Richard Smith
Mark L. Reed III Distinguished Professor
Department of Statistics and Operations
Research

Conghe Song
Associate Professor
Department of Geography

Donna Surge
Associate Professor
Department of Geological Sciences

David Weber
Professor
Departments of Epidemiology, Medicine and
Pediatrics
Gillings School of Global Public Health and
School of Medicine

Jason West
Assistant Professor
Department of Environmental Sciences &
Engineering

Richard Whisnant
Professor of Public Law and Government
School of Government

Peter S. White
Professor
Department of Biology
Director
North Carolina Botanical Garden

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Table of Contents

Preface iii

Contributors vi

List of Figures ix

Acronyms and Chemical Formulas xi

Executive Summary xii

Chapter 1 Overview of Global Climate Change 1

Chapter 2 Environmental Impacts 29

Chapter 3 Public Health Effects of Climate Change 68

Chapter 4 Mitigation and Adaptation 94

Chapter 5 Recommendations 149

Appendices
A: Hurricane and drought scales 156
B: Climate models 158
C: Glossary 159
D: Uncertainties due to economic assumptions 163

E: Potential for solar energy technology 169

Endnotes 171


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List of Figures
Figure 1.1. Global human-caused greenhouse gas emissions sources in 2004. 5
Figure 1.2. Atmospheric concentrations of carbon dioxide, methane, and nitrous oxide 6
Figure 1.3. Share of total human-caused greenhouse gas emissions, by sectors. 6
Figure 1.4. The greenhouse effect 7
Figure 1.5. Global temperature land-ocean anomaly (°C), 1880-2007 8
Figure 1.6. Glacial retreat, South Cascade Glacier, Washington. 9
Figure 1.7. Scenarios for GHG emissions from 2000 to 2100 14
Figure 1.8. Statewide average annual temperatures in the Southeast snce 1895. 16
Figure 1.9. Trends in annual total precipitation in North Carolina, by region 17
Figure 1.10. Monthly drought by climate division in North Carolina 19
Figure 1.11. Number of category 1-4 hurricanes affecting NC during the 20th Century 20
Figure 1.12. Cyclone strength and sea surface temperature 21
Figure 1.13. The strongest cyclones appear to be getting stronger. 22
Figure 1.14. Estimating the effect of climate change on tropical storms 23
Figure 1.15. Plots of Atlantic hurricane counts, major hurricanes, and U.S. landfall hurricanes 24
Figure 1.16. Stations used in computing climate normals 25
Figure 1.17. Temperature projections with 95% probability intervals 26
Figure 1.18. Precipitation projections with 95 percent probability intervals 27

Figure 2.1. North Carolina drought monitor rating of drought severity in October 2007 31
Figure 2.2. Trends in seasonal precipitation (in inches) from the 1895-2007 33
Figure 2.3. Central Coastal Plain of North Carolina 38
Figure 2.4. Sea level rise due to thermal expansion and increase in ocean mass 40

Figure 2.5. Areas of coastal North Carolina with elevation less than one meter. 41
Figure 2.6. Contaminant loads from intense storms (hurricanes) in North Carolina 47
Figure 2.7. Examples of harmful CyanoHAB blooms worldwide 52

Figure 3.1. Potential health effects of climate variability and change 70
Figure 3.2. Composition of atmosphere by gas 71
Figure 3.3. Hardiness zone maps, 1990 and 2006 77
Figure 3.4. Excess mortality plotted against temperature for the 2003 heat wave in France 90

Figure 4.1. Electricity use in North Carolina compared to other states. 98
Figure 4.2 Energy use in North Carolina (1977-2000) 100
Figure 4.3 North Carolina energy use by sector 100
Figu
re 4.4 Breakdown of NC energy costs by state agency (FY 2002). 101
Figure 4.5 Economic analysis of energy efficiency measures for a new home 101
Figure 4.6. Wind energy potential in North Carolina 103
Figure 4.7. Energy sites in North Carolina 109
Figure 4.8. Hatteras Village after Hurricane Isabel of 2003 119
Figure 4.9. Vehicle miles traveled on interstate highways in North Carolina. 120
Figure 4.10. Per capita carbon emissions in North Carolina, by sector 121
Figure 4.11. Transportation mode used for the journey to work in North Carolina. 122
Figure 4.12. Walking and driving trips to the commercial center of a new urban neighborhood 124
Figure 4.13. Top 10 most costly hurricanes in US history (insured losses, 2005 dollars) 128

x
Figure 4.14. Underwriting gain or loss in Florida homeowners insurance, 1992-2007 130
Figure 4.15. Dam sites in North Carolina 138
Figure 4.16. CAPAG mitigation option recommendations ranked 141

Figure D1. Lost property values due to sea-level rise induced by climate change 166

Figure D2. Effects of assumptions about discount rates on present value of property lost 167

List of Tables
Table 1.a. Types of uncertainty 11
Table 1.b. Likelihood scale 11

Table 3.1. Effects of weather and climate on infectious diseases in North America . 79
Table 3.2. Possible Impacts of Climate Change on Infectious Diseases in North Carolina. 81
Table 3.3. Examples of multilevel adaptive measures for some anticipated health outcomes 93

Table 4.1 Energy bills and household energy 99
Table 4.2. Potential energy production from animal wastes in NC. 104
Table 4.3. Renewable energy potential in NC 105
Table 4.4. Options for mitigating GHG emissions in North Carolina 140
Table 4.5. Mitigation options in energy, transport and land use 144

Table B1. Climate Models Used for Future Projections 157
Table D1. Lost Property Values Due to Sea-Level Rise for Four North Carolina Counties 166


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Acronyms and Chemical Formulas
AMO – Atlantic Multidecadal Oscillation
CAMA – Coastal Area Management Act
CDC – Centers for Disease Control and Prevention
CO
2
– carbon dioxide
CH
4

– methane
DO – dissolved oxygen
FEMA – Federal Emergency Management Agency
GCM – general circulation model, global climate model
GHG – greenhouse gas
HAB – harmful algal bloom
IPCC – Intergovernmental Panel on Climate Change
N
2
O – nitrous oxide
NO
2
– nitrogen dioxide
NOAA – National Oceanic and Atmospheric Administration
NRC – Nuclear Regulatory Commission
PDSI – Palmer Drought Severity Index
PM – particulate matter
PM
2.5
– particulate matter (fine particles 2.5 micrometers and smaller)
PM
10
– particulate matter (coarse particles between 2.5 and 10 micrometers)
ppb – parts per billion
ppm – parts per million
RCM – regional climate model
RPS – renewable portfolio standard
RSLR – relative sea level rise
SRES – Special Report on Emissions Scenarios
SO

2
– sulfur dioxide
US ACE – United States Army Corps of Engineers
VMT – vehicle miles traveled
VOC – volatile organic compound



xii
Executive Summary

Overview of Climate Change
While there is still uncertainty and disagreement on climate change forecasts, the major scientific
organizations have agreed that human activity is contributing significantly to global climate change.
In addition, scientists generally agree on the following four points:
1) The concentration of greenhouse gases is increasing.
2) Greenhouse gases warm the environment.
3) Global mean temperatures have increased.
4) Climate change is not a uniform process, but includes substantial climate variation.

In North Carolina, these changes could lead to:

Hotter summers, warmer winters
- While North Carolina has not seen the same extent of
warming in the 20
th
century as other areas, climate model forecasts suggest an increase in
temperature locally to range from 4-7
o
F by the latter half of the 21

st
century. The rising
temperatures will affect energy use, public health, recreation, and even the types of plants
that can grow in the state.


More extreme events
- Rising temperatures are expected to bring more heat waves,
hurricanes and intense storms. The extreme weather would cause greater flooding inland and
along the coast. Increased drought occurrence and intensity would put greater stress on
existing water supplies and ecosystems.


Rising seas
- Melting glaciers and “thermal expansion” of the oceans will lead to rising sea
levels. This will exacerbate coastal erosion and inundation and could render uninhabitable
large swaths of low-lying coastal areas. There is a chance, although with high uncertainty,
that rapid melt and break-up of polar ice sheets could raise sea levels substantially over a
very short period (a decade) leading to a catastrophic loss of coastal land.


xiii
Environmental Impacts of Climate Change in North Carolina
Water resources
Increased storm intensity can result in more damaging and catastrophic flooding, greater stormwater
runoff and erosion, and increased drought occurrence. The intensification of the water cycle may
require greater storage capacity, more efficient storage management, and significantly increased
water -use efficiency to manage drought. Enhanced stormwater runoff will increase the loading of
nutrients, sediment and contaminants into streams, rivers, reservoirs and coastal waters. The
increased loads will affect drinking water quality and freshwater and marine ecosystems and will

require proactive stormwater management. Saline water intrusion in coastal aquifers will also be a
problem due to both rising sea levels and declines in coastal aquifers due to insufficient recharge and
overpumping. Land use is an important, interacting process that should be carefully managed to
mitigate climate change impacts.
Air quality
Increasing temperatures are expected to worsen air quality. Two pollutants of chief concern are
ozone and fine particulate matter (from road dust, diesel emissions and wildfires). The longer the
warm, sunny period without significant wind or rainfall, the more ozone accumulates. Both ozone
and fine particulate matter can enter the lungs and cause health problems. Extended warm seasons
can enhance high ozone, pollen and fine particulate concentrations (due to fire, greater energy
demand from conventional power plants, longer growing and flowering seasons and longer rain-free
periods), providing multiple and reinforcing sources of low air quality.
Ecosystem health
Biodiversity may be threatened. Warming could move optimal habitat for native plants and animals
to the north, reducing their viability in North Carolina and increasing competition from species
from other locations. However, the lack of ecosystem corridors for species migration with the
disappearance of good habitat in North Carolina may lead to extinction rather than relocation. Many
pathogens reside in the natural environment and warmer environments may increase their
metabolism, adding threats to natural ecosystems, agriculture and human health. Some impacts may
be mixed. For example, warming tends to increase growing season length and may increase carbon
sequestration, reducing the rate of climate warming. However, increased drought may limit forest

xiv
growth and its ability to absorb atmospheric carbon dioxide. In addition, increased fire risk due to
elevated temperature and longer dry spells may reduce forest cover and release carbon stored in
plant biomass to the atmosphere, posing significant hazards to suburban communities built in and
around forest stands.
Marine and coastal resources
North Carolina’s coastline is vulnerable to sea level rise. The combined increase of inland flooding,
coastal surges, and elevated sea levels will exacerbate coastal inundation. Barrier beaches are

especially vulnerable due to their low elevation and exposure to subtropical storms, inadvertent
effects of development, and loss of sand supply from impounded rivers. Sea levels could rise
gradually – up to 5 feet by the end of the century. However, the potential collapse of the Greenland
or Antarctic ice sheets would cause sea levels to rise by more than 20 feet over a decade. The
probability of this event is unknown, but would lead to a catastrophic loss of large coastal areas
around the globe.

Runoff from increased storm intensity would transport more nutrients and sediment into coastal
waters, increasing the frequency of harmful algal blooms. Increased water temperature and
stratification would contribute to algal blooms, low oxygen events, and fish kills. Increased water
temperature, sedimentation, resuspension of bottom sediment during storms, and increased nutrient
content of freshwater and coastal waters can increase the concentration of, and exposure to, harmful
pathogens.

Public Health Impacts of Climate Change in North Carolina
The effects of climate change could affect human health by direct and indirect processes. Direct
impacts could include increased incidence and intensity of heat waves, intense storms and coastal
surges, and other extreme weather. Indirect effects could include worsening air and water quality,
and increased abundance of, and exposure to, pathogens and disease vectors.
Climate hazards (heat, storms)
Heat waves will increase with global warming due to the increase in mean temperature and the
increased variability of weather conditions. Impacts would be felt most by vulnerable populations
such as the elderly, the poor, and people with pre-existing health conditions. The greatest impacts

xv
have occurred in dense, northern cities (e.g., Chicago) where there are a large number of residences
without air conditioning, and lower adaptation to hot weather. The July 1995 heat wave in Chicago
led to over 500 heat-related deaths. While North Carolina urban areas are not as dense as northern
cities, increasing urbanization in North Carolina will increase the urban heat island effect,
exacerbating heat wave impacts in our largest cities. The potential for energy shortages during major

hot spells would threaten the availability of indoor air conditioning, possibly worsening heat-related
mortality and morbidity.
Air quality
Increased ozone and fine particulate matter are significant public health threats, contributing to
cardiopulmonary and respiratory illness, reduced lung function, and chronic bronchitis, asthma and
allergic disease. Similar effects are evidenced from photochemical smog. Air pollution effects are
particularly acute among children and the elderly. Increased temperature also results in earlier
flowering and longer pollen seasons for some plants, which will exacerbate conditions for people
suffering from pollen allergies. There is an interactive effect of heat and pollution, where health
effects caused by a combination of high-temperature and high-pollution events exceed what would
be expected from each event independently.
Infectious disease
There are approximately 1500 infectious agents that can cause human disease. The disease ecology
of pathogens is often complex and dependent on climate. In general, warmer temperatures increase
the survivability of disease pathogens in the environment, either by reducing winter cold which
drives down populations, by facilitating survival of host organisms (such as mosquitoes and ticks), or
by increasing the active season for the hosts. Increased temperatures and alteration of wet and dry
periods could lead to enhanced habitat for disease vectors that require temporary water bodies for
breeding (e.g., mosquitoes) and lead to increases in infectious disease occurrence. Public health
screening and preventative action will need to be enhanced to follow these threats.

In addition to vector-borne illnesses, direct ingestion of pathogens in the water, indirect ingestion
through contaminated seafood, and entry of pathogens through open wounds can result in serious
illness. Warmer temperatures are likely to favor replication of these organisms in water and may
increase disease rates. The potential for transport of pathogens from large confined animal feeding

xvi
operations into freshwater and estuaries during major storms is of particular concern in North
Carolina, which has a large swine industry in the coastal plain. More severe storms may promote
transmission of pathogens from feedlots to receiving water bodies.

Mitigation and Adaptation
A number of opportunities exist to proactively mitigate global climate change and/or to adapt to the
environmental impacts. Mitigation requires reduction of greenhouse gas emissions and other human
causes of climate change. The state should take the lead in developing and adopting alternatives to
fossil fuels; developing and retrofitting communities, industry and agriculture to be more energy and
carbon efficient; and finding methods to capture, absorb and sequester emissions and atmospheric
carbon. Actions taken today to reduce energy consumption and replace fossil fuels with “clean”
energy will help mitigate climate change and create significant co-benefits economically,
environmentally, and in human health.

There remains significant disagreement among UNC faculty on alternative energy sources. Each
source involves tradeoffs, that is, between one type of environmental impact (carbon dioxide
emissions) for another (water quantity and quality, nuclear waste disposal, aesthetics), or between
increased intermittency of energy availability (wind, solar) and transmission requirements.

Transportation is now the largest energy-using sector in the state, exceeding the residential,
commercial and industrial sectors, due to an increase in population and miles driven per capita.
While greater fuel efficiency will decrease emissions per mile, current trends suggest this will be
outstripped by increased passenger travel and freight transport. Therefore, solutions must involve
more than increased fuel efficiency; they must include development patterns that facilitate the use of
public transit (as well as biking and walking) and the creation of more efficient freight distribution
networks. Land use planning can help mitigate climate change effects by guiding the location, type
and amount of development, and adapt to the impacts of climate change, such as sea level rise, by
redirecting future settlement patterns away from hazard areas.

Much of our infrastructure for water supply, flood protection, transportation, and energy is reaching
the end of its expected lifetime. The opportunity exists to reinvest in and redesign civil infrastructure

xvii

by developing more efficient energy, land use, transportation and water supply systems, improve air
and water quality, and create jobs.

A bellwether industry, property and casualty insurance, has already taken steps in response to the
threats posed by climate change. Financial exposure to catastrophic losses (such as those from
Hurricanes Floyd and Katrina) has led insurers to pull out of the market in coastal states. It is no
coincidence that the insurance industry is among the most active commercial sectors voicing
concern and urging action on climate change. Some state governments have become the insurer of
last resort, placing the government and the public at risk.

The enormous potential costs and impacts of uncontrolled climate change, even if uncertain, require
that the state improve its understanding and preparation. It is possible that climate change may turn
out to be less severe than projected. It is also possible, however, that the impacts will be much
worse, particularly considering the nonlinear behavior of the global climate system, which could lead
to very large shifts in prevailing climate conditions. Preparing in advance – for example, by moving
away from fossil fuels, improving energy efficiency, and changing development patterns – will yield a
number of advantages in terms of economic, environmental, and quality of life hazard reduction.


1
1
climate change forecasts, the major scientific
tributing significantly to global climate change.
 Greenhouse gases warm the environment.

and
years 2071-2100 show a consistent warming of
out 5°F over all regions and seasons, slightly lower in winter than the other three seasons, with a
high level of confidence that the warming trend is genuine. The models also project an increase of
precipitation over all seasons and regions, but with wide probability intervals, reflecting greater

uncertainty about the direction of future change.


Overview of Global Climate Change Chapter 1
Chip Konrad, Jacqueline MacDonald, Peter Robinson, Richard Smith and Jason West

Chapter Summary

While there is still uncertainty and disagreement on
organizations have agreed that human activity is con
In addition, scientists generally agree on the following points:
 The concentration of greenhouse gases is increasing.
 Global mean temperatures have increased.
 Climate change is not a uniform process, but includes substantial climate variation.
 Climate change and its impacts will be felt very differently in different parts of the world.

North Carolina experiences large variations in its climate, with major differences among the
mountains, Piedmont and coastal region. Predictions of long-term climate change are largely carried
out using models of global atmospheric circulation coupled with dynamic models of the oceans
land. Model projections for North Carolina for the
ab

2
Impacts of Climate Change on North Carolina
Hotter summers, warmer winters - Climate model forecasts suggest an increase in temperature locally to
range from 4-7
o
F. The rising temperatures will affect energy use, public health, recreation, and even
the types of plants that grow in the state.

More extreme events - Rising temperatures are expected to bring more heat waves, hurricanes and
intense storms. The extreme weather would cause greater flooding inland and along the coast and,
during dry periods, would put greater stress on existing water supplies.

Rising seas - Melting glaciers and “thermal expansion” of the oceans will lead to rising sea levels. This
will exacerbate coastal erosion and inundation and could render uninhabitable large swaths of low-
lying coastal areas.

Recommendations
Although climate change is uncertain, the risk of inaction is great. Even if climate change turns out
to be less severe than projected, there are a number of things the state can do today that will benefit
the economy, environment and public health, such as reducing our reliance on fossil fuels,
promoting alternative sources of energy (solar, wind) and energy efficiency, improving the design of
communities to facilitate walking, biking and the use of public transportation, and discouraging
people from developing in hazard-prone areas such as floodplains. We recommend that the state:
 Take steps today to reduce greenhouse gas emissions and improve its capacity to adapt to
climate change impacts. This could include providing incentives for solar and wind energy as
well as initiating a cooperative program with neighboring states to reduce greenhouse gas
emissions.
 Support additional research geared toward improving our understanding of climate change
impacts. This will help target and increase the efficiency of mitigation and adaptation policy.
Continued, long-term monitoring programs will reduce uncertainty and allow adaptive
management of key resources.

3
The primary cause of recent
climate change
OVERVIEW OF GLOBAL CLIMATE CHANGE
Global climate change has brought about heated debate
among academics, politicians, and the general public. Some

have said that it will be the defining environmental issue of
the next generation and indeed for the next century. Others
question whether climate change is occurring at all or whether
the impacts will be as dire as predicted. After all, climate has
fluctuated naturally in the past, although the warming in the
last 50 years is unprecedented. While some doubters remain,
several leading scientific organizations agree that human
activity is a major cause of recent climate change, as noted in
the sidebar. In addition, Naomi Oreskes, Professor of History
and Science Studies at the University of California, San Diego,
analyzed 928 abstracts of articles on climate change published
in peer-reviewed scientific journals from 1993 to 2003. Three-
quarters of the articles “either explicitly or implicitly accept
the consensus view” of human-influenced climate change,
while “none of the papers disagreed with the consensus
position.” The remaining quarter took no position, dealing
with methods or analysis of climate trends from the distant
past.
1
Certainly, global climate change has engendered
passionate responses because so much is at stake.
Intergovernmental Panel on Climate
Change (IPCC)
“Most of the observed increase in global
average temperatures since the mid-20th
century is very likely due to the observed
increase in anthropogenic GHG
concentrations.”
1

National Research Council
“Most scientists agree that the warming in
recent decades has been caused primarily
by human activities that have increased the
amount of greenhouse gases in the
atmosphere.”
2


American Meteorological Society
“…strong observational evidence and
results from modeling studies indicate that,
at least over the last 50 years, human
activities are a major contributor to climate
change.”
3


American Geophysical Union
“Many components of the climate system
– including the temperatures of the
atmosphere, land and ocean, the extent of
sea ice and mountain glaciers, the sea level,
the distribution of precipitation, and the
length of seasons – are now changing at
rates and in patterns that are not natural
and are best explained by the increased
atmospheric abundances of greenhouse
gases and aerosols generated by human

activity during the 20th century.”
4


American Association for the
Advancement of Science
“The scientific evidence is clear: global
climate change caused by human activities
is occurring now, and it is a growing threat
to society.”
5


Climate change could affect the world around us in profound
ways, with potential influences on many aspects of our
economy and our lives. Likewise, the use of fossil fuel energy
that leads to emissions of greenhouse gases is also central to
every aspect of our modern lives and the global economy.
Climate change challenges us to develop a better
understanding of our world and to seek innovative solutions
to meeting our energy needs. It also challenges our decision
makers to confront large technical and political problems and


4
to consider how decisions made today will affect people and
the environment over the next century. For example,
regulatory strategies such as a market-based cap-and-trade
system or a carbon tax would require careful consideration of
economic and social costs and benefits over time. Similarly,

investments in alternative energy sources such as wind, solar
and geothermal, could reduce greenhouse gas emissions.
1
IPCC, 2007. Climate Change 2007: Synthesis
Report. Contribution of Working Groups I, II and
III to the Fourth Assessment Report of the
Intergovernmental Panel on Climate Change [Core
Writing Team, Pachauri, R.K and Reisinger, A.
(eds.)]. IPCC, Geneva, Switzerland, p. 39]
2
National Research Council. (2008). Understanding
and Responding to Climate Change: Highlights of
National Academies Reports (2008 Edition), p. 2.
3
American Meteorological Society. (2007). Climate
Change: An Information Statement of the
American Meteorological Society. Bull. Amer. Met.
Soc., 88. Adopted by AMS Council on 1 February
2007, p. 2
4
American Geophysical Union. (2007). Human
Impacts on Climate. Adopted December 2003,
revised and reaffirmed December 2007. Accessed
10-31-2008.

climate_change2008.shtml.
5
American Association for the Advancement of
Science. (2006). AAAS Board Statement on Climate
Change. Approved December 9, 2006. Accessed

10-31-2008.
/>hange/mtg_200702/aaas_climate_statement.pdf.

This chapter provides a summary of the scientific knowledge
on global climate change, including causes, trends, and likely
outcomes.

Scientific Understanding of Climate
Change
While there are uncertainties in our understanding of climate
change, scientists agree on a number of key points:
1. Atmospheric concentrations of greenhouse gases have
increased.
2. Greenhouse gases tend to warm the earth.
3. The earth is warming.
4. Climate and weather are becoming more variable over time.
5. Climate change and its impacts will be felt very differently in different parts of the world.
Each of these points is discussed in more detail below.

1. Atmospheric concentrations of greenhouse gases have
increased
Greenhouse gases are comprised primarily of carbon dioxide, methane, nitrous oxide and
fluorocarbons, with the largest share made up of carbon dioxide (Figure 1.1). Water vapor, not
shown in Figure 1, is also a greenhouse gas. Since the Industrial Revolution, and particularly in the
last several decades, the concentration of carbon dioxide and other greenhouse gases has increased
rapidly (Figure 1.2), due mostly to human activities and the burning of fossil fuels.
2
From ice cores
and other records, scientists have estimated that carbon dioxide concentrations held fairly steady at

5
about 280 parts per million, or ppm, for over 1000 years leading up to the Industrial Revolution
(Figure 1.2). In the 1950s, when direct measurements began, concentrations had increased to about
315 ppm. In 1958, Dr. Charles Keeling began collecting weekly samples of air at the Mauna Loa
Observatory, 11,000 feet above sea level in Hawaii. He compiled the longest, continuous record of
carbon dioxide concentrations in the atmosphere. Currently, the concentration of carbon dioxide is
about 380 ppm and is expected to exceed 550 ppm – almost twice the preindustrial levels – this
century, depending on future emissions of greenhouse gases. These recent and rapid increases in
concentration are unambiguously due to human activities, as demonstrated through chemical
signatures in the isotopic composition (different atomic weights of elements like oxygen, carbon and
nitrogen) of these gases.






Figure 1.1. Global human-
caused greenhouse gas
emissions sources in 2004.
For a description of these
gases, see the glossary.
Source: IPCC 2007.
3

Similarly, methane concentration (currently about 1.8 ppm) is more than double preindustrial levels
(about 0.7 ppm). Concentrations of methane and CO
2
in ice cores changed little in the past 10,000
years, until the Industrial Revolution. Current concentrations of these greenhouse gases are greater
than at any time in at least the past 650,000 years. Concentration shifts in the past coincided with the
huge changes in climate between the Ice Ages and Interglacials – relatively warm periods where ice
cover was limited to the poles.

6

Figure 1.2.
Atmospheric
concentrations of
carbon dioxide,
methane, and nitrous
oxide over the last
2,000 years, in parts
per million (ppm) or
parts per billion (ppb).
Greenhouse gas
concentrations in the
atmosphere have
increased rapidly since
about 1800, primarily
due to human activities
in the industrial era.
Source: IPCC 2007.4

Greenhouse gases come from a variety of sources, including the combustion of fossil fuels and
changing land use – in particular, deforestation (Figure 1.3). Methane derives from both industrial
activities (e.g., coal mining, natural gas operations, and landfills) and from agriculture (e.g., rice
paddies, cows, and hogs). Although methane’s atmospheric concentration is much lower than that
of carbon dioxide, it is estimated to be 21 to 25 times more effective at trapping heat over a 100-year
period.
5

erms
:



Figure 1.3. Share of total
human-caused
greenhouse gas
emissions from different
sectors, in 2004, in t
of carbon dioxide (CO
2
)
equivalent. Source
IPCC 2007.
6



7
Nitrous oxide, another important greenhouse gas, results mainly from agriculture and has increased
significantly with the introduction and rapid increase in chemical fertilizer applications. Several other

human-made gases, including refrigerants, are also powerful greenhouse gases.

2. Greenhouse gases tend to warm the earth
Our understanding of how certain gases warm the earth goes back more than a century. In the
1860s, Irish physicist John Tyndall observed that CO
2
, methane, and water vapor all absorb heat in
the form of longwave (infrared) radiation, and that these gases do not absorb solar radiation in the
same way (Figure 1.4). Consequently, heat from the sun (shortwave radiation) passes more easily
through the atmosphere than does the longwave radiation given off by the earth. By trapping some
of this heat in the atmosp
here, greenhouse gases cause the earth’s temperature to rise more than it
would otherwise.

Figure 1.4. Greenhouse
gases trap some of the
heat radiating from the
earth. The greenhouse
effect is a natural
phenomenon that keeps
the earth warm. Source:
NASA 2000.
7

3. The earth is warming
Global temperatures at the surface of the earth have increased rapidly since the mid-1800s. Global
temperature records show unequivocally that the earth’s temperature has increased by 1.4°F
±0.34°F (0.76°C±0.19°C) since the late 1800s, with most of that warming happening in the past 50
years.
8
According to NASA’s Goddard Institute for Space Studies (GISS), the eight warmest years
on record have all occurred since 1998, and the 14 warmest years in the record have all occurred
since 1990.
9
(See Figure 1.5).

8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
Year
Temperature Anomaly (°C)
5-year Mean
Annual Mean

Figure 1.5. Global temperature land-ocean anomaly (°C), 1880-2007, defined as the
difference from the average temperature of the base period (1951-1980). The 14
warmest years in the global temperature record have all occurred since 1990. The blue

points (annual means) in the box from 1990-2007 show the warmest years. Adapted
from: NASA 2007
10
(box added).

The observed pattern of change is broadly consistent with scientific understanding of the impacts of
global warming, including greater temperature change over land than oceans and in winter than in
summer. Other observed changes are consistent with this warming, including increasing atmospheric
water vapor, increasing ocean heat content, rising sea level, reduced Arctic sea ice cover, and
receding alpine glaciers (Figure 1.6). Trends in precipitation are less uniform around the world, with
some places showing increases and others decreasi
ng, but heavy precipitation events, including
hurricanes, may be changing in intensity (see discussion below). In summary, climate change is
happening.

4. Climate and weather are becoming more variable
In addition to changes in average climate conditions, over the last two decades the variability of
weather has been increasing, consistent with the predictions of climate change models, discussed