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Climate and Energy Part 1: The Future, Rev b

By John Benson

October 2019

1. Introduction This is the first paper in a series that will describe how climate change will impact energy utilities (electric and natural gas), water utilities and their infrastructure. Note that this paper is a recent update of the original paper, posted in May, 2018. I will also update the other papers in this series concurrently with this one. As with other of my posts, this series is intended to educate, in this case it's primarily targeted at utility engineers and facility engineers. I will travel much further into the future than I generally like to do, but I will try to build everything on currently known facts.

Engineers and scientists believe that they can do anything they can visualize. This series of papers will help the readers visualize how our climate works, why it's changing, what impacts of the changes will be, how mitigation might work, and how all of the above can impact our energy and water infrastructure.

There will be three papers in this series. The next two are:

https://www.energycentral.com/c/ec/climate-and-energy-part-2-impacts-infrastructure-rev-b

https://www.energycentral.com/c/ec/climate-and-energy-part-3-mitigating-climate-change-rev-b

2. Predicting the Future We know the root cause of climate change: rapidly increasing greenhouse gases (GHGs) in our atmosphere. Climate change is also called global warming, and although this term is technically correct (on average, the global climate is warming), it is also confusing. Weather and climate are very dynamic. Thus as the climate changes, some places will be warmer (on average) and some, cooler. Some areas will be warmer during parts of the year, and cooler during other parts of the year. Note that weather is NOT the same as climate. Climate is the accumulation of global weather over years or longer. Although the weather is, in part, produced by climate-related oscillations and changes, it is mostly produced by chaotic variations.

However the average matters over long periods. For instance, the sea level would rise by over 20 feet if the entire Greenland Ice Sheet melted. If the Antarctic Ice Sheet also melted, it would contribute an additional 200 feet of sea level rise. Although this is not likely for several centuries, the rate of net ice-melt in these sheets could cause substantial sea-level rise in this century, and that rate is strongly dependent on the average air and sea temperature (among other factors) around these ice sheets over the remaining years in this century. Furthermore, our ability to predict how the climate will change between now and the end of the century will help us predict if we will be dealing with a two-foot average sea-level rise (bad for low-lying areas) or a four-foot average seal-level rise (really bad…) in year 2100.

The rest of this section will be devoted defining how our climate works and how climatologists predict the future.

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2.1. Days of Future Past A primary key in predicting how our climate will behave in the future is understanding how it behaved in the past. Although current climate change is occurring much more rapidly than at any time in the past (due to extremely high greenhouse gas levels), we can learn much from specific periods in the past where the climate transitioned through conditions similar to those we will encounter in upcoming decades and centuries.

Climate leaves fingerprints in the paleontological record. The most important of these are trapped remnants of the past that are preserved in ice and sediment. These can (for instance) tell us the temperature and atmospheric composition hundreds of thousands or even millions of years ago. These remnants are called proxy records and by examining these, the climatologists can measure or extrapolate conditions at the time of recording.

Climatologists are also developing climate models. To calibrate these models, they use them to predict the known climate for the recent past (because relatively high-resolution global climate data is available for this period) and then run them on periods from the distant past. This does two things: (1) the models (or more likely model-suites) can be made more accurate by being run over many known past periods, and (2) the climatologists gain a better understanding of the science of climate change.

The following is a brief description of the most important tools.

Coupled Model Inter-comparison Project Phase 6 (CMIP6): This is currently the most comprehensive framework for coordinating climate change experiments.1 This project (CMIP5) was originally managed by Lawrence Livermore National Lab, but with the recent de-emphasis of climate research by the current administration, it is being transferred to the Working Group on Coupled Modelling (WGCM) under the World Climate Research Program (WCRP) in Genève, Switzerland.

Community Earth System Model (CESM) & Accelerated Climate Modeling for Energy (ACME): ACME is a DOE model based on CESM. This is a multi-laboratory project developing a leading-edge climate and Earth system simulation.

Energy Exascale Earth System Model (E3SM): This is the most recent evolution of ACME (note the deletion of the word "Climate"). It is designed to use the most powerful (exascale) computing arrays. It is being managed by Lawrence Livermore National Lab. For additional information go through the link in the reference here. 2

There are also specialized models (combined with general-purpose models like the above in a suite) for important parts of our climate, like the Greenland and Antarctic Ice Sheets. These include Albany/FELIX. Albany is a program developed by Sandia National Laboratory. It is used to solve partial differential equations using finite-element analysis. FELIX (Finite Elements for Land Ice eXperiments) was also developed by Sandia. This is an application that uses Albany to simulate the evolution of ice sheets and their influence on Sea-Level Rise.

2.2. Major Effects on Earth’s Climate Two factors strongly affect how heat enters the earth’s biosphere (oceans, land and lower atmosphere). The first moderates and the second accelerates the rate of heating.

1 See https://www.wcrp-climate.org/wgcm-cmip/wgcm-cmip6 for more information on CMIP6. 2 Energy Exascale Earth System Model (E3SM) main site, https://e3sm.org/

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1. The mass of the atmosphere is 5 x 1015 tons, and the combined mass of the oceans is 1.5 x 1018 tons. So the oceans are 300 times more massive than the atmosphere. Also, unlike the land masses, the oceans have currents that can distribute heat and GHGs to the depths. About 93% of the excess heat energy stored by the Earth over the last 50 years is found in the oceans.

2. Accurate measurement of the arctic ice cap started in the late 70s with the first earth-monitoring satellites. Even then the ice cap was shrinking rapidly:

a. 1979 until 1996 the area of the ice cap was shrinking 3% per decade.

b. 1997 until 2007 shrinkage was 10.7% per decade.

c. Models predict that there will be no summer sea ice in the arctic by 2050.

Note that the floating ice in the Arctic is normally called an ice cap. The deep ice on Greenland and Antarctica are normally called ice sheets.

Snow reflects most of the solar radiation that strikes it back into space. Ocean water, bare land and vegetation-cover absorb most of the solar radiation that strikes it. Thus the loss of snow-cover (including the arctic ice cap) accelerates the rate of earth’s warming. Ice sheets experience darkening as they melt due to dust, carbon particles and algae. This further accelerates their melting.

2.3. Heat Measurements and Scenarios Greenhouse gasses (GHGs) cause radiative forcing. Radiative forcing (hereafter “forcing”) quantifies this change in net heat-energy flows in watts per square meter (W/m2) at the top of the atmosphere. Positive forcing warms the surface, and negative forcing cools the surface. The total forcing caused by humans currently (relative to 1750) is about 3 W/m2. The table below identifies the main GHGs and their contributions to radiative forcing since 1979.3

Year CO2 CH4 NO2 CFC-12 CFC-11 Minor* Total

1979 1.027 0.419 0.104 0.092 0.039 0.031 1.712

1980 1.058 0.426 0.104 0.097 0.042 0.034 1.761

1981 1.077 0.433 0.107 0.102 0.044 0.036 1.799

1982 1.089 0.44 0.111 0.108 0.046 0.038 1.831

1983 1.115 0.443 0.113 0.113 0.048 0.041 1.873

1984 1.14 0.446 0.116 0.118 0.05 0.044 1.913

1985 1.162 0.451 0.118 0.123 0.053 0.047 1.953

1986 1.184 0.456 0.122 0.129 0.056 0.049 1.996

1987 1.211 0.46 0.12 0.135 0.059 0.053 2.039

1988 1.25 0.464 0.123 0.143 0.062 0.057 2.099

1989 1.274 0.468 0.126 0.149 0.064 0.061 2.144

1990 1.293 0.472 0.129 0.154 0.065 0.065 2.178

1991 1.313 0.476 0.131 0.158 0.067 0.069 2.213

3 Wikipedia article on Radiative forcing, https://en.wikipedia.org/wiki/Radiative_forcing . This uses public

domain material from the NOAA document: Butler, J.H. and S.A. Montzka (1 August 2013). "THE NOAA

ANNUAL GREENHOUSE GAS INDEX (AGGI)". NOAA/ESRL Global Monitoring Division

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Year CO2 CH4 NO2 CFC-12 CFC-11 Minor* Total

1992 1.324 0.48 0.133 0.162 0.067 0.072 2.238

1993 1.334 0.481 0.134 0.164 0.068 0.074 2.254

1994 1.356 0.483 0.134 0.166 0.068 0.075 2.282

1995 1.383 0.485 0.136 0.168 0.067 0.077 2.317

1996 1.41 0.486 0.139 0.169 0.067 0.078 2.35

1997 1.426 0.487 0.142 0.171 0.067 0.079 2.372

1998 1.465 0.491 0.145 0.172 0.067 0.08 2.419

1999 1.495 0.494 0.148 0.173 0.066 0.082 2.458

2000 1.513 0.494 0.151 0.173 0.066 0.083 2.481

2001 1.535 0.494 0.153 0.174 0.065 0.085 2.506

2002 1.564 0.494 0.156 0.174 0.065 0.087 2.539

2003 1.601 0.496 0.158 0.174 0.064 0.088 2.58

2004 1.627 0.496 0.16 0.174 0.063 0.09 2.61

2005 1.655 0.495 0.162 0.173 0.063 0.092 2.64

2006 1.685 0.495 0.165 0.173 0.062 0.095 2.675

2007 1.71 0.498 0.167 0.172 0.062 0.097 2.706

2008 1.739 0.5 0.17 0.171 0.061 0.1 2.742

2009 1.76 0.502 0.172 0.171 0.061 0.103 2.768

2010 1.791 0.504 0.174 0.17 0.06 0.106 2.805

2011 1.818 0.505 0.178 0.169 0.06 0.109 2.838

2012 1.846 0.507 0.181 0.168 0.059 0.111 2.873

2013 1.884 0.509 0.184 0.167 0.059 0.114 2.916

2014 1.909 0.5 0.187 0.166 0.058 0.116 2.936

2015 1.938 0.504 0.19 0.165 0.058 0.118 2.973

2016 1.985 0.507 0.193 0.164 0.057 0.121 3.027

*The "minor" column includes 14 gases, particulates and aerosols (including water vapor).

In order to have a common framework for future scenarios, climate scientists have created representative concentration pathways (RCPs) – a set of scenarios representing different levels of forcing. The forcing is estimated for year 2100. Four scenarios are used: 2.6 W/m2 for RCP2.6, 4.5 W/m2 for RCP4.5, 6.0 W/m2 for RCP6.0, and 8.5 W/m2 for RCP8.5. Note that we have already exceeded RCP2.6.

2.4. Ocean and Atmosphere Currents and Oscillations Other than the amount of solar energy we receive from the sun, the most important element in determining climate is how the oceans and atmosphere flow. Rapid climate changes are generally caused by disruptions in these flows. This section will define the major elements of these currents and how they are driven to flow and oscillate.

Oscillations in the oceans affect each other, and also affect oscillations in the atmosphere. The best example of this is the El Niño / Southern Oscillation (below).

2.4.1. Meridional Overturning Circulation (MOC)

The MOC is the main engine that drives the flow of water, energy and nutrients around the global oceans. The MOC is composed of surface flows that are primarily driven by

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wind, and much slower deep-sea flows that are driven by down-welling salty water. The salty water is created by evaporation of surface water in warm currents resulting higher salt content than in the ocean as a whole. Saltier water is heavier than less salty water (and cooler water heavier than warmer) so the current eventually plunges downward. Thus the MOC is sometimes called Thermohaline Circulation (see figure below).

Summary of the path of the MOC. Blue paths represent deep-water currents, while red paths represent surface currents.4

Down-welling (deep water formation) occurs most in a single area in the North Atlantic, south and east of Greenland (see map below). Warm water flowing northward in the North Atlantic MOC (a.k.a. the Gulfstream) evaporates and becomes more salty, and as it moves northward it cools, until it plunges into the deep ocean.

Leading climatologists believe that the Atlantic MOC has slowed down by about 15% in recent decades. This is mainly caused by meltwater (which is fresh) from the melting Greenland Ice Sheet diluting the saltiness of the northern Gulf Stream and slowing down-welling. This slowing reduces warm flow from southern waters, which heats them up and could accelerate the melting of the Antarctic Ice Sheet by warming the water around glacier footings flowing from the ice sheet.

2.4.2. El Niño / Southern Oscillation (ENSO)

El Niño is an oscillation of Pacific Ocean temperatures and currents. The Southern Oscillation is the corresponding oscillation of atmospheric temperatures and currents. Together these are El Niño / Southern Oscillation, or simply ENSO.

The atmospheric changes during the different phases of the Southern Oscillation are complex and global in their range. These are best explained by an article from the NOAA Earth Systems Research Laboratory linked below.

http://www.esrl.noaa.gov/psd/enso/enso.description.html

2.4.3. Other Oscillations

The Atlantic Multidecadal Oscillation: is an oscillation in an ocean current affecting the North Atlantic Ocean, in particular its sea surface temperature. The period of oscillation is 50 to 70 years.

The Pacific Decadal Oscillation: is an ocean-atmosphere oscillation occurring in the northern Pacific with a period of about 10 years. Like ENSO, the PDO has a positive

4 Wikipedia article on “Thermohaline Circulation

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(warm) phase and a negative (cool) phase. The climate impact of this is seen mainly on the Pacific coast of North America, but some effects are seen throughout the world.5

The Southern Annular Mode: is the north and south movement of the wind that circles Antarctica and blows from the west toward the east. It cycles about every five years.

The Northern Annular Mode: is a time-varying index that is a function of surface atmospheric pressure. When the AO (arctic oscillation) index is positive, pressure is low in the polar region. The AO index has a positive and negative phase, and oscillates from one phase to the other, but does not appear to have any particular period of oscillation.

3. Current Predictions for 2100 The primary effect of climate change is trapping heat in the biosphere. Currently the lower atmosphere’s average temperature increase is rather minimal. Current U.S. average annual temperature increased by 1.8°F from 1901 to 2016. Most of this increase (1.2°F) has occurred since about 1986. Earth’s 2016 surface temperatures were the warmest since modern recordkeeping began (in 1880), according to independent analyses by NASA and the National Oceanic and Atmospheric Administration (NOAA). This makes 2016 the third year in a row to set a new record for global average surface temperatures.6

Note that most of the information in this section are drawn from the Fourth National Climate Assessment (NCA4), Volume I, https://science2017.globalchange.gov/ .

The figures below show the regional North American temperature increases and the global average temperature increase for the scenarios described in section 2.3.

5 Wikipedia article on “Pacific Decadal Oscillation”. 6 https://climate.nasa.gov/news/2537/nasa-noaa-data-show-2016-warmest-year-on-record-globally/

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A warmer atmosphere can hold and release more water. On average heavy rain events have increased dramatically in the U.S., although they have decreased in the Southwest. See the figures below.

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In general, the trends shown in the above maps should continue into the foreseeable future.

Other major impacts include:

Snowfall depth and water-equivalent in the Western and Southern U.S. have decreased. These metrics have increased in parts of the Northern U.S.

The frequency and intensity of land-falling "atmospheric river" events will increase on the U.S. West Coast, leading to increased flooding.

Large wildland fires have increased and will continue to increase in the Western U.S. (including Alaska). This is mainly in response to rising temperatures drying vegetation.

Modeling indicates an increase in intensity and precipitation rates for Atlantic and Pacific hurricanes.

The global mean sea-level is very likely to rise by one to four feet by 2100.

The local sea-level rise is likely to be more than the global average in the Eastern and Gulf coast areas.

The conditions described by the last three bullets above are very likely to result in extreme flooding in many U.S. Atlantic and Gulf coastal areas.