Geog 5 Part 3 (Discussion Segment)

IPCC Fifth Assessment Report, Working Group 1

"Climate Change 2013: The Physical Science Basis" presents a global assessment of climate change science. Warming in the climate system is unequivocal, with many of the observed changes unprecedented over decades to millennia: warming of the atmosphere and the ocean, diminishing snow and ice, rising sea levels and increasing concentrations of greenhouse gases. Each of the last three decades has been successively warmer at the Earth's surface than any preceding decade since 1850. 95% certainty that human activity is the dominant cause of observed warming since the mid-20th century.

What causes the majority of emissions in low-income countries?

AFOLU: agriculture and forestry projects.

PDI

Aggregates storm intensity, frequency, and duration, provides a measure of total hurricane power over a hurricane season.

Lake Champlain

Basically the water shed of Vermont.

Observed temperature and precipitation trends in New England.

Both observed trends are positive.

Climate Change is Simple

CO2 traps heat. Stable climate over human civilization. Modern humans have been on Earth for 200,000 years. Civilization has existed for 12,000 years. 125 KYA sea levels were 6 m higher, and continental temperatures were 1-3 degrees celsius warmer. The Earth is warming. The Earth will continue to warm in the future. It is extremely likely that climate change is anthropogenic.

Enhancing Carbon Sequestration: Carbon Capture and Storage

Captured from point sources or filtered from the air. Variety of industrial processes can capture CO2 pre- or post-combustion. Filter made of an absorbent resin that reacts with carbon dioxide in the air to form a solid, steam causes the solid to release the CO2. Inject CO2 into porous rock, store underground or in the deep ocean. ~300 tC/year. ~2.7 trillion/year for 9 GtC. Leakage. Ocean acidification risks. Unintended consequences and quesitonable feasibility.

Global Water Scarcity Trend

Climate Change doesn't necessarily make it more scarce. Population change contributes to greater scarcity.

Communicating Uncertainty: What does confidence synthesize?

Confidence (degree of certainty) synthesizes evidence and agreement.

Projected trend in Days above 90 fahrenheit in the Northeast.

Days above 90 degrees fahrenheit are projected to increase across the Northeast.

Geoengineering

Deliberate large-scale manipulation of the planetary environment to counteract anthropogenic climate change.

Sustainable Development

Development that meets the needs of the present without compromising the ability of future generations to meet their own needs.

Climate-Resilient Pathways

Development trajectories that combine adaptation and mitigation to realize the goal of sustainable development. They can be seen as iterative, continually evolving processes for managing change within complex systems. Resilience-raising pathways increase the resilience space between social stressors (innermost circle) and biophysical stressors (outermost circle).

What are the economic impacts of climate change?

Economic impact estimates vary in their coverage of economic sectors and depend on a large number of assumptions, many of which are disputable, and many estimates do not account for catastrophic changes, tipping points, and many other factors. Estimates of global annual economic losses for temperature increases of ~2 degrees celsius between 0.2 and 2.0% of income. For most economic sectors, the impacts of drivers such as population, age structure, technology, regulation, prices, and governance are projected to be large relative to climate change. Impacts different between and within countries.

Impacts

Effects on natural and human systems.

What dominates emissions in high-income countries?

Emissions dominated by sources related to energy supply and industry.

Antarctica is Gaining Ice - Rebuttal

Examination of one location is always dangerous. Interior of East Antarctica is gaining land ice, overall Antarctica has been losing land ice at an accelerating rate. Antarctic sea ice is growing despite a strongly warming Southern Ocean. Ozone levels over Antarctica have dropped causing stratospheric cooling and increasing winds, which enhance sea ice production.

Feedback Mechanisms

Feedback mechanisms are systems in which changes in one variable lead to changes in another. They enhance or damp climate change. Negative: feedback inhibits further change in a variable. Positive: feedback magnifies further change in a variable.

Indonesian Forest Fires, 1997-1998

Fires set to clear land for palm oil and rice plantations burned out of control. Spread to dry, flammable peatlands during one of the region's driest seasons on record. Fires subsided in early 1998. Event estimated to have accounted for 40% of global carbon emissions for the period burning.

Interpreting graph of population against emissions.

Gray lines (slope 1) - constant annual per capita emissions. Steeper lines show where ghg emissions grow faster than population. Flatter lines ("more gradual") show where population growth outpaces ghg emissions growth.

Growing season length projected trend.

Growing season length is projected to increase 43 days by late-century.

National Climate Assessment: Precipitation

Heavy precipitation events are expected to increase. Increase in frequency of extreme daily precipitation events defined as a daily amount that now occurs just once in 20 years. Doubling in RCP 2.6, quintupling in frequency in RCP 8.5.

Mitigation

Human intervention to reduce the sources or enhance the sinks of greenhouse gases.

Externality

Impact on individual or societal production and consumption possibilities from a human activity that are not accounted for by agents responsible for the activity.

Atmospheric Water Vapor Feedback

Important positive feedback. Warmer air holds more water vapor (is a greenhouse gas) - Clausius Clapeyron. Surface temperature increases -> evaporation increases -> atmospheric absorption of longwave radiation increases -> longwave emission to surface increases.

Enhancing Ocean Carbon Sequestration: Iron Fertilization

In large areas of the ocean iron is the limiting nutrient to phytoplankton growth. Add iron, phytoplankton grows, absorbs carbon, dies, sinks, and sequesters carbon in the deep ocean. Early climate models suggested intentional iron fertilization across entire Southern Ocean could erase 10-25 percent of the world's annual total carbon emissions. Disrupts bottom of oceanic food chain. Unintended consequences. Effectiveness uncertain.

Climate Change: Impact on Agricultural Production

Increased CO2 can enhance carbon assimilation in some crops, but not in others. Generally increases water use efficiency in all plants. However, heat stress and drought can devastate yields. Changes in all aspect of climate change - temperature and precipitation distributions, growing season length, radiation, wind - are important.

By how much has global mean sea level risen from 1901 to 2010.

It has risen by 0.19 m.

What has caused this rise in global mean sea level?

It is a result of ocean thermal expansion (0.8-1.4 mm/year) and changes in glaciers (0.39-1.13 mm/year), the Greenland ice sheet (0.25-0.41 mm/year), the Antarctic ice sheet (0.16-0.38 mm/year), and land water storage (0.26-0.49 mm/year).

What are the risks and rewards associated with SRM?

It is a way to act quickly to lower temperatures rapidly in the event of a climate crisis. However, it does not affect CO2 levels, and thus, fails to address the wider effects of rising CO2, such as ocean acidification. It may have unintended consequences. Furthermore, SRM may create moral hazard for policymakers, and engaging in SRM should require global consensus.

European Heat Wave 2003

Likely the hottest summer in Europe since 1500. Average summer temperatures over Europe exceeded the 1961-1990 mean by 2.3 degrees celsius. 35,000+ heat-related deaths were reported across Europe. Very likely that human influence has at least doubled the risk of a heatwave exceeding 1.6 degrees celsius, a threshold mean summer temperature that was exceeded in 2003, but in no other year since the start of the instrumental record in 1851.

What tiers of evidence are there?

Limited, medium, and robust.

2 Degree Celsius Mitigation Scenarios

Mitigation scenarios in which it is likely that the temperature change caused by anthropogenic GHG emissions can be kept to less than 2 degrees celsius relative to pre-industrial levels are characterized by atmospheric concentrations in 2100 of about 450 ppm CO2eq.

Hurricane Trends

North Atlantic Hurricanes may be more severe. Strong upward trend in Atlantic PDI, and a downward trend in eastern North Pacific. Significant increase in the strength and in the number of the strongest hurricanes in the North Atlantic over this same time period.

Two Hurricane Basins

North Atlantic Ocean and Eastern North Pacific Ocean

Maximum Antarctic Sea Ice Extent

Occurred in 2013. Ice surrounding Antarctica reached its annual winter maximum and set a new record.

Ice-Albedo Feedback

Positive Feedback. Affects both the melting and accumulation of ice. Snow and ice cover decreases -> albedo decreases ->absorption of solar radiation increases -> surface temperature increases -> snow and ice cover decreases.

Projected monthly snowfall trend.

Projected to decrease 50% by late-century.

Burden Sharing

Reducing the sources or enhancing the sinks of greenhouse gases from historical or projected levels, usually allocated by some criteria, while sharing the cost burden across countries.

Reflecting Solar Radiation: Clouds

Seed marine stratocumulus clouds with sea water particles (cloud condensation nuclei) to enhance cloud droplet number. Increases the albedo of clouds ~3%. Fleet of ~1500 boats, ~$2 billion total cost.

Ocean Model (AOGCM) or Fixed Sea Surface Temperatures with Ocean Flux Parameterization (AGCM)

Solve equations involving atmospheric radiation, convective clouds and precipitation, resolvable scale clouds and precipitation, planetary boundary layer, and surface physics. (Class 18 slide 6).

Carbon Dioxide Removal (CDR):

Technique that acts to remove CO2 from the atmosphere.

Projected temperature and precipitation trends.

Temperature is projected to increase by 4.5 degrees celsius by late-century. Precipitation is projected to increase by 10% by late-century.

Risk

The potential for consequences where something of value is at stake and where the outcome is uncertain.

Exposure

The presence of people, ecosystems, resources, or assets that could be adversely affected.

Adaptation

The process of adjustment to actual or expected climate and its effects. In human systems, adaptation seeks to moderate or avoid harm or exploit beneficial opportunities. In some natural systems, human intervention may facilitate adjustment to expected climate and its effects.

Vulnerability

The propensity to be adversely affected.

Sea Level Rise: Trend

The rate of sea level rise since the mid-19th century has been larger than the mean rate during the previous two millennia.

How can climate change adaptation be managed?

Through iterative risk management, which consists of scoping (identifying risks, vulnerabilities, and objectives, and then establishing decision-making criteria), analysis (identifying options, assessing risks, and evaluating tradeoffs), and implementation (implementing decision, monitoring, reviewing & learning).

North Atlantic Warming Hole

(Fresh water from melt decreases density) Atlantic Meridional Overturning Circulation weakening, reducing the flow of warm water which decreases local ocean temperatures.

Solar Radiation Management (SRM)

(Geoengineering technique that involves taking action to) reflect a small percentage of the sun's light and heat back into space.

Sustainability

A dynamic process that guarantees the persistence of natural and human systems in an equitable manner.

Heat Waves

A robust and dangerous climate change impact.

What is the current state of climate change adaptation?

Adaptation is becoming embedded in some planning processes, with more limited implementation of responses. Adaptation experience is accumulating across regions in the public and private sector and within communities.

IPCC Fifth Assessment Report, Working Group II

"Climate Change 2014: Impacts, Adaptation, Vulnerability" presents an assessment of observed impacts and future risks of, and vulnerability and exposure of human and natural systems to, climate change. Observed impacts of climate change are widespread and consequential. Differences in vulnerability and exposure arise from non-climatic stressors and multidimensional inequalities, which shape risks from climate change. Impacts from recent extreme climatic events, such as heat waves, droughts, floods, and wildfires, show significant vulnerability and exposure of some ecosystems and many human systems to climate variability.

IPCC Fifth Assessment Report, Working Group III

"Climate Change 2014: Mitigation of Climate Change" assesses literature on the scientific, technological, environmental, economic, and social aspects of mitigation of climate change.

What is the degree of certainty in each key finding of the assessment based on?

The type, amount, quality, and consistency of evidence and the degree of agreement.

Climate Has Not Significantly Warmed Since 1998 - Rebuttal

1998 was an unusually hot year due to a strong El Nino. 10 years is a short time period to see climate change. The planet has continued to accumulate heat since, both on the land surface and in the ocean.

Global Precipitation Measurement

Advances understanding of water and energy cycles. Measures: intensity and variability of precipitation, three-dimensional structure of cloud and storm systems, microphysics of ice and liquid particles within clouds, amount of water falling to Earth's surface. Applications: weather forecast models, climate models, integrated hydrologic models of watersheds, forecasts of hurricanes, landslides, floods and droughts

Transformation

A change in the fundamental attributes of natural and human systems. Transformation reflects strengthened, altered, or aligned paradigms, goals, or values towards promoting adaptation for sustainable development, including poverty reduction.

Reflecting Solar Radiation: Paint it White (Rooftops)

All urban roofs and pavement painted white globally would create an ~2.2 Gt C/year offset. Cool roofs reduce cooling-energy use in air conditioned buildings and increase comfort in unconditioned buildings. Cool roofs and cool pavements mitigate heat islands, improving outdoor air quality and comfort. Only offsets a relatively small amount of carbon emissions. Some benefits are questioned: lower local temperature means less water evaporates and rises up to eventually form clouds, allowing more sunlight to reach the Earth's surface and leading to higher temperatures overall.

Reflecting Solar Radiation: Space Mirrors

Cloud of a trillion mirrors 2 ft in diameter but only one-five-thousandth of an inch thick forming a cloud twice the diameter of Earth. Filter out about 2% of sunlight. Total cost ~$800 billion - $10 trillion (10 trillion in present costs, 800 billion in future costs)

North America Warming Hole

Due to evapotranspiration-precipitation-circulation coupling. Natural variability in pacific sea surface temperatures, atmospheric moisture in Caribbean Sea and Gulf of Mexico atmospheric moisture.

Reflecting Solar Radiation: Stratospheric Sulfate Aerosols

Inject 5 Tg of SO2 into lower stratosphere (over the tropics) annually. Dispersed using balloons, planes, "garden hose in the sky". Total cost ~$250 million/year. May alter precipitation patterns globally, especially monsoons. If stopped, warming would be even more rapid. Sulfate aerosols also destroy ozone.

Adaptation Limit

For an actor, system, and planning horizon, no adaptation options exist, or an unacceptable measure of adaptive effort is required, to maintain societal objectives or the sustainability of a natural system.

Solution Space

Framework for assessing not only the impacts and challenges but also the opportunities and synergies for dealing with climate change. For addressing changing risks through adaptation and disaster risk reduction.

Projected sea level rise

Global mean sea level will continue to rise during the 21st century. Under all RCP scenarios, the rate of sea level rise will very likely exceed that observed during 1971-2010.

Trends in anthropogenic ghg emissions by country income.

High income and upper middle income countries now responsible for roughly equivalent quantities of emissions. Lower middle income and lower income countries pollute less and haven't seen as much of a growth trend as upper middle income countries (not all developing countries created equal).

Natural Disasters: Hurricanes

Hurricanes are among the most devastating natural disasters. 6/10 most costly weather events in US since 1842 were Hurricanes.

Intergovernmental Panel on Climate Change

Intergovernmental body jointly established in 1988 by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP). Provides policymakers with the most authoritative and objective scientific and technical assessments. Beginning in 1990, released Assessment Reports, Special Reports, Technical Papers, Methodology Reports. Shared the Nobel Peace Prize with Al Gore in 2007.

Risks and rewards of CDR?

It addresses the root cause of climate change, and faces relatively low uncertainties and risks. On the other hand, the reduction of global temperatures via CDR would be slow, and CDR may have unintended consequences.

What does downscaling do?

It provides climate data with higher spatial resolution. Accomplished using statistics and historical data to approximate. Hard to do smaller cells in original data because computers are computationally limited.

What's happening to the Western Antarctic Ice Sheet?

It's collapsing. The eventual loss of a major section of West Antarctica's ice sheet "appears unstoppable". West Antarctic Ice Sheet identified as the single largest threat of rapid sea level rise. Region contains enough ice to raise global sea levels by 4 feet. West Antarctic Ice Sheet, if melted completely would raise global sea level by about 16 feet.

Why is disproportionate warming projected in winter?

Less snow than historically the case, so lower albedo, which means winters warm more than summers.

What is the most important negative feedback?

Longwave Radiation-Temperature Feedback is the most important negative feedback. As surface warms, amount of energy it emits increases, stabilizing temperature.

Levels of agreement?

Low, medium, or high.

Enhancing Terrestrial Carbon Sequestration: Greening the Desert

Plant fields of fast growing trees such as eucalytpus across the deserts of the Sahara and Australian outback. Irrigate using seawater treated by a string of coastal desalination plants. Forested deserts could draw down around 8 Gt C/year. Total cost ~$1.9 trillion/year. Tree cover would change local and possibly global precipitation. Feasibility uncertain.

What are New Hampshire summers projected to feel like?

Projected to feel like North Carolina summers.

How is adaptation related to mitigation?

Prospects for climate-resilient pathways for sustainable development are related fundamentally to what the world accomplishes with climate-change mitigation.

How will projected sea level rise be distributed?

Sea level rise will not be uniform. By the end of the 21st century, it is very likely that sea level will rise in more than about 95% of the ocean area. About 70% of the coastlines worldwide are projected to experience sea level change within 20% of the global mean sea level change.

Class 19 Slides 6-8

Series of flow-charts on "Climate Resilience Pathways and Opportunity Space", "IPCC Climate Change Solution Space", "Climate Change Adaptation through Iterative Risk Management"

Resilience

The capacity of social, economic, and environmental systems to cope with a hazardous event or trend or disturbance, responding or reorganizing in ways that maintain their essential function, identity, and structure, while also maintaining the capacity for adaptation, learning, and transformation.

Hazard

The potential occurrence of a natural or human-induced impact that may cause damage to health, ecosystems, or property.

Sequestration

The uptake of carbon containing substances in terrestrial or marine reservoirs. Includes direct removal of CO2 from the atmosphere through land-use change, afforestation, reforestation, revegetation, carbon storage in landfills, soil carbon enhancement in agriculture, carbon dioxide capture and storage.

Ocean-Atmosphere Interaction

Thermohaline Circulation - circulation system of oceans driven by differences in temperatures (warmer, less dense) and salinity (less saline, less dense). Melting of glaciers could freshen water near Greenland, decreasing density, reducing Atlantic Meridional Overturning Circulation

Anthropogenic GHG emission trend.

Total anthropogenic GHG emissions have continued to increase over 1970-2010 with larger absolute decadal increases toward the end of this period.

Two-Track Science Approach

Track 1: Model Improvement and Intercomparison (are these models accurate?) Track 2: Climate Change Multi-Model Assessment (putting models together, what do they project?)

USGCRP

U.S. Global Change Research Program was established in 1989 and mandated by Congress in the Global Change Research Act of 1990 to "assist the Nation and the world to understand, assess, predict, and respond to human-induced and natural processes of global change".

Five qualifiers used in communicating uncertainty:

Very low, low, medium, high, and very high.

Reflecting Solar Radiation: Volcanoes

Volcanoes are a natural form of geoengineering. Three major eruptions have occurred in the past 50 years. Eruptions push gases high into the stratosphere, where sulfur dioxide combines with water to form sulfuric acid, a very reflective aerosol. Associated with 0.2-0.3 degree celsius drops in global temperature that last 1-3 years.