Climate Change: Laying out the Problem Science Cafe Richard B. Rood January 24, 2007

Some Climate News National Oceanographic and Atmospheric Administration (NOAA) // World Data Center for Meteorology // National Climatic Data Center – –State of the Climate –

What is Science? When used in the application of the scientific method –Hypothesis is a proposition that can be tested whether or not it is valid. Formally, by experiment, often by ability to predict. –Theory is systematically organized knowledge based on tested hypotheses and principles. –Principles are basic truths from which hypotheses are drawn and on which theories are built. –Facts are information that is objectively real or true.

Attributes of Science-based Knowledge An important attribute of knowledge derived scientifically is that it is based in observation and tested. There is also independent testing by others (like an audit). Further, new tests are posed to challenge theories, which lead to refinement and strengthening of the theory. Sometimes the theories are proven wrong – at least in part.

The motivator: Increase of CO 2 (Keeling et al., 1996)

What parameters/events do we care about? Temperature Water –Precipitation –Evaporation –Humidity Air Composition –Air quality –Aerosols –Carbon dioxide Winds Clouds / Sunlight Droughts Floods Extreme Weather

What do predictions tell us?

Note: There is consistency from many models, many scenarios, that there will be warming. (1.5 – 5.5 C) Also, it’s still going up in 2100! Basic physics of temperature increase is very simple, non- controversial. The prediction: *

Projected Global Temperature Trends IPCC ‘ temperatures relative to Special Report on Emissions Scenarios Storyline B2 (middle of the road warming).

Uncertainty If you were to assign uncertainty –Regional, seasonal predictions are more uncertain than latitudinal, annual predictions are more uncertain than global, time-average prediction.

Systematic Temperature Changes Global Temperature increase 1.5 – 4.5 C Poles warm faster than globe, especially the North Pole. Land warms faster than ocean. Night warms faster than day Spring starts earlier Autumn starts later

Update: 2000s have continued trend Update: Troposphere warming is observed. Correction of satellite temperature

Water Water vapor in atmosphere will increase (It’s a greenhouse gas.) Precipitation will increase Evaporation will increase (It’s warmer.) Snow cover will be less over most continents. Snow could increase in Greenland and Antarctica?

Storms, Drought, Floods Extreme events are expected to occur more often and to be more extreme.

Update: Papers in 2005 that hurricane intensity has increased Update: Papers in 2006 that ice is melting more rapidly

Sea level predictions 0.11 to 0.43 meters due to thermal expansion, warming of the ocean water 0.01 to 0.23 meters due to melting of continental glaciers Greenland:  meters ??? Antarctica:  meters ??? These are likely to change appreciably with the new IPCC. Comes out in February.

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Systematic Look Freeze-free periods are getting longer Snow cover decreasing Growing season longer Spring is earlier CO2 annual cycle is getting larger Sea ice is decreasing Mountain glaciers are decreasing Mountain ecosystems are changing …

Regional issues identified in assessments Reduction in water level of the Great Lakes (1-5 feet) –Temperature rise (20 th Century and predicted) –Precipitation increase (20 th Century and predicted) Human health in cities –Heat waves / Reduced extreme cold –Air quality worse in heat Agriculture and forestry –Soil moisture decrease, more drought –Growing season longer –Changes in insects, disease, fire … Ecosystem – water and air quality –Lower stream flows, punctuated with floods –Changes in flora and fauna (land and water) due to temperature –Invasive species External factors from other regions –Water for western half of U.S. Great Recycling and Northern Development Canal (James Bay in Canada) –Water for eastern half of the U.S. –Hydroelectric facilities –Pollution from/to other regions Ice reduced, shoreline damage decreased, less snow removal, more land, …

What do with do with this information? Is this information about probable climate change accurate and interpretable? –Is it robust? –How often and fast does it change? Is it consequential? –Are there risks if we ignore it? –Are there risks if we believe it? How does this information about probable climate change relate to humans and the things that humans do?

How do we get our information? Direct research, generation of new knowledge Review of the primary source literature Journalism Editorials Entertainment Public Outreach from Information Holders Popular literature Texts, formal education Peer-reviewed evaluations of the state of the knowledge of the field

How do we evaluate this knowledge? How do we evaluate (validate?) this information? –Personal experience Is it hotter where I live? –Relative to what we know and believe How does it impact us? Does it cost something? –In some absolute sense? Look at past observations Look at ability to predict Look at quality of observations Look at consistency of theory, robustness of hypothesis Attribution of change, cause and effect This is where we will spend most of the first group of lectures

SCIENTIFIC INVESTIGATION OF CLIMATE CHANGE What are the pieces which we must consider? (what are the consequences) Belief SystemValuesPerceptionCultural MandateSocietal Needs information flow: research, journals, press, opinion, … Security Food Environmental National Societal Success Standard of Living...???... ECONOMICSPOLICY “BUSINESS”PUBLIC HEALTH SOCIAL JUSTICE ENERGY RELIGION??????

Energy The climate change problem and energy policy are correlated, currently, they are completely intertwined. By most standards, energy use is directly related to societal success. Hence virtually all elements of society are stakeholders.

World primary energy supply in 1973 and 2003 Source: International Energy Agency 2005 * megaton oil equivalent *

Map Projection Geographic Map Description This map illustrates historic cumulative carbon emissions from (as a percentage of global output) at a country-level. As indicated on the map, areas with highest cumulative emissions are predominantly found in "northern" richer nations such as the U.S. (at 27%) and the EU (at 18%). Alternatively, lowest carbon emissions are found in economically challenged

Top 20 Emitting Nations, 2000

Source: IEA, Key World Energy Data 2005

World Average CO2 Emissions Per Capita, 2000: 1.56 Tons Source: Boden, 2003 The Result of Global Inequality is Gross Carbon Inequality Rich countries emit around metric tons carbon annually per person, while the middle income nations are around 0.6 mT and the poorest around 0.02 mT

POLICY

Science, Mitigation, Adaptation Framework

Some definitions Mitigation: The notion of limiting or controlling emissions of greenhouse gases so that the total accumulation is limited. Adaptation: The notion of making changes in the way we do things to adapt to changes in climate. Resilience: The ability to adapt. Geo-engineering: The notion that we can manage the balance of total energy of the atmosphere, ocean, ice, and land to yield a stable climate in the presence of changing greenhouse gases.

Global cooling? Why do we think that our predictions today are more robust than these predictions from the 1970s?

Let’s look at just the last 1000 years Surface temperature and CO 2 data from the past 1000 years. Temperature is a northern hemisphere average. Temperature from several types of measurements are consistent in temporal behavior.  Medieval warm period  “Little ice age”  Temperature starts to follow CO 2 as CO 2 increases beyond approximately 300 ppm, the value seen in the previous graph as the upper range of variability in the past 350,000 years.

What do we know from model experiments and evaluation (validation) with observations With consideration of solar variability and volcanic activity, the variability in the temperature record prior to 1800 can be approximated. After 1800 need to consider the impact of man –Deforestation of North America –Fossil fuel emission –Change from coal to oil economy –Clean air act? Only with consideration of CO 2, increase in the greenhouse effect, can the temperature increase of the last 100 years be modeled. We will revisit this in more detail after we learn about models.

Consideration of the past record Recorded human history has taken place in a period of relatively warm climate. Since the last ice age there have been warm and cold periods where the global average temperature varies by approximately 0.5 degrees F. These changes have been accompanied by discernable impact on human activities. In the past 100 years we have seen an increase of #### degrees. –Do you feel that there has been impact on humans? In the next 100 years we expect to see ~ 3.0 – 10.0 rise in global average temperature. It is reasonable to expect impact on human activities.

Behavior of water; Phase change Differences for the Future ( years)  ~100 ppm CO 2 (Already)  > ppm CO 2 certain  ~ 8-20 C polar T difference  ~ 2-6 C global average T difference New Regimes of Climate Behavior? ICE AGE ~200 ppm CURRENT (360 ppm) NEW AGE? ~500 ppm Differences from Past (20,000 years) ~100 ppm CO 2 ~ 20 C polar T difference ~ 5 C global average T difference Time gradient of CO 2 changes, 2 orders of magnitude (100 times) larger.