Climate Change Research

Contributed by Claire Kelly

Explanation of source links: Throughout the research below, you will find links of three types. The first and most frequent type is to primary sources such as governmental agencies. The second is to nonprofit groups that generally use government data or their own research to support their philanthropic mission. We have tried to use the least biased of these, or when in doubt, we have identified their bias. The third is to articles in periodicals or newspapers that we find to be of interest. These are not meant to be construed as original sources, and in some cases may not be accessible, depending on a reader's frequency of prior visits to the linked periodical or newspaper.

What is the definition of Climate Change?

Climate change refers to a change in regional and global climate patterns associated with an increase in global average temperatures. Such increases in temperature are a result of increased levels of atmospheric greenhouse gases (GHG) that trap heat in the atmosphere. The increase in GHGs is the result of human activity beginning with the period of industrialization. The consequences of these changing climate patterns include the melting of the polar ice caps, protracted drought conditions, rising sea levels, and more frequent instances of extreme weather.

HOW HAVE GLOBAL AVERAGE TEMPERATURES INCREASED?

As shown in the following chart, scientists have estimated that global average temperatures have increased by one degree centigrade since 1850, the beginning of industrialization. 

WHAT ARE GHGS? 

GHGs include carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), fluorinated gases, and water vapor. 

HOW DO GHGS WARM THE ATMOSPHERE? 

The sun emits light in the form of shortwave radiation that passes through our atmosphere. Some of this light is absorbed and some is re-emitted by the Earth’s cooler surface as infrared radiation. The GHGs present in the atmosphere capture and absorb a portion of this radiation, thereby warming the atmosphere.

The capacity of GHGs to trap heat in the atmosphere is referred to as the greenhouse effect. The greenhouse effect was discovered in the 1800s when scientists calculated that the Earth was 59 degrees (F) warmer than could be accounted for by the sun’s rays alone.

WHICH GHGS CONTRIBUTE THE MOST TO WARMING?

Water vapor is the most abundant GHG and accounts for approximately 60% of the warming effect. The second is CO2, followed by methane. For the reasons explained below, however, CO2 is the most important.    

DOESN’T WATER VAPOR OCCUR NATURALLY?

Yes, water vapor occurs naturally in the atmosphere. However, as the Earth’s temperature rises, it increases the amount of atmospheric humidity (the amount of water the atmosphere can hold), thereby increasing the amount of heat retained by the atmosphere. This cycle is referred to as “water vapor feedback.” While water vapor is technically the largest contributor to average temperatures, it is the initial heat retention caused by other GHGs that increases water vapor’s warming effect. Water vapor also condenses and falls as precipitation when it reaches maximum density. Other GHGs, like CO2, can remain in the atmosphere for thousands of years.

SO, CO2 IS THE MOST IMPORTANT GHG?

Yes, for three reasons. First, it contributes directly to heat retention in the atmosphere. Secondly, it contributes to the “water vapor feedback” loop, and thirdly, it remains in the atmosphere the longest. Methane, the third largest contributor, is more efficient at trapping radiation than CO2, but only has an atmospheric lifetime of 12 years. 

BUT ISN’T CO2 ALSO NATURALLY OCCURRING? 

Yes, CO2 is one of carbon’s three gaseous components. Carbon is a chemical element of the periodic table and is widely distributed naturally. It can be found in rocks such as limestone, fossil fuels such as coal and oil, living organisms, oceans, and the atmosphere. Carbon naturally moves through the food chain. Plants convert atmospheric carbon into sugar molecules through photosynthesis, and those plants are digested by animals for energy. Respiration, excretion, and decomposition release this carbon back into the soil or atmosphere as CO2 to complete the cycle. In the atmosphere, CO2 levels are measured in parts per million (ppm).

IF CO2 IS NATURAL, HOW DOES NATURE REGULATE IT?

If undisturbed by human activity, nature manages a massive and complicated carbon cycle that results in equilibrium of CO2 levels. Some natural functions of the planet and its vegetation emit CO2 into the atmosphere while others absorb it. 

Carbon storage is referred to as a “stock” or “pool.” The largest stocks are the continental crusts and upper mantle of the Earth. Earth’s vegetation and oceans (the second and third largest stocks respectively) are responsible for storing and pulling large amounts of CO2 out of our atmosphere. All vegetation does not have the same carbon appetite or storage practice. Warm, tropical regions tend to store carbon above-ground and have some of the fastest turnover of that carbon, while the cool, boreal forests have large stores of belowground carbon and can hold that carbon for—on average—more than three times longer than tropical forests. 

HOW ARE ATMOSPHERIC CO2 LEVELS MEASURED?

CO2 levels in the atmosphere are measured on regular intervals by a number of organizations, including the National Oceanic and Atmospheric Administration’s (NOAA) Earth Systems Research Laboratory. The laboratory does so by measuring the molecules within air samples and expresses the results in PPM. 

HOW HAVE ATMOSPHERIC CO2 LEVELS CHANGED OVER TIME?  

Measurements from the NOAA over a 60-year period illustrate a definitive and steady increase in CO2 concentrations, as shown in the graph below, from the first recording of 316 ppm in 1958 to 414 ppm as of 2020. Annual atmospheric CO2 levels vary naturally around 5 ppm between seasons, but are increasing by around 2 ppm annually, and the annual increase is getting larger as well. 2018 had the highest single-year increase on record, with carbon growing by 2.87 ppm. This is a relatively recent trend. Data over the past two millennia show a substantial increase in not only CO2 but also CH4 and N2O.

HOW DO HUMAN EMISSIONS AFFECT THE EARTH’S NORMAL CARBON CYCLE?

The human contribution of carbon emissions overwhelms the natural capacity of the Earth’s oceans and vegetation to reabsorb carbon. The result is a net increase in atmospheric carbon. The most common illustration of this is the bathtub analogy. 

In this analogy, the “bathtub” is the Earth’s atmosphere, and the “faucet” represents both manmade and natural processes that release “water” (carbon) into the tub. The “drain” represents the natural processes that can lower the water (carbon) level. With only natural processes controlling the faucet, the water level can fluctuate at manageable levels within the tub, but with the addition of manmade processes, the tub can fill, and even overflow. Further, human activity such as deforestation can “clog” the drain, slowing down the removal of water. 

HOW HAS HUMAN ACTIVITY AFFECTED THE NATURAL CO2 LEVELS?

The harnessing of energy through combustion of coal and oil was central to industrialization and the development of modern transportation systems, but this process emits CO2 and water vapor into the atmosphere. Under natural circumstances, this carbon may have remained in the ground for millions of years. Anthropogenic (originating in human activity) emissions and land use have shifted 19-36% of carbon out of these stores into the atmosphere and ocean. More than half of historic fossil fuel carbon emissions have occurred in the last three decades. 

HOW MUCH ARE CO2 LEVELS EXPECTED TO RISE BY 2100, AND HOW MUCH WOULD THE PLANET WARM AS A RESULT?  

Predicting the future of CO2 levels is difficult inasmuch as the levels will be affected by human behavior over the period measured. Therefore, scientists create models based on different assumptions of fossil fuel use. The International Energy Agency (IEA) estimates that if nothing is done to reduce emissions, the world is on track to increase total CO2 levels by as much as two times the current level over the balance of the century. Models assuming varying efforts to reduce emissions result in lower levels. 

“Climate sensitivity,” or the amount that temperature will increase as CO2 concentrations increase, is also difficult to determine, but the range has been estimated to be enough to result in 1.5-4.5 degrees Celsius of warming. Models that look at warming through the end of the century estimate that the likely upper bound is five degrees, although the worst case would be a warming of eight degrees.

WHAT NATURAL FEEDBACK LOOPS ARE TRIGGERED BY CLIMATE CHANGE?

NASA climate scientists categorize factors affecting climate change into the following categories: forcing, feedbacks, and tipping points. Forcing initially drives climate changes and includes solar irradiance and GHG emissions. The second category is climate feedbacks, which are defined as processes that can either amplify (positive feedbacks) or diminish (negative feedbacks) the effects of climate forcings. While forcings may lead to some amount of warming by themselves, it is the feedbacks that accelerate the warming process.

Oceans and ice: A surface’s ability to reflect solar energy is known as “albedo,” and varies between 0 (absorbs all energy) and 1 (reflects all energy). (The loss of ice—which due to its light color has an albedo of 0.5 to 0.7—is a positive feedback. The darker ocean, with an albedo of only 0.06, absorbs much more solar energy, therefore causing more melting of ice and continued warming. This is considered a “very strong” positive feedback. Sea ice with snow is even better and can have an albedo of up to .9, reflecting up to 90% of incoming solar radiation, and insulating the ice. 

Water vapor: Water vapor is one of the strongest climate feedbacks. As the planet warms, the atmosphere holds more water vapor. The increased water vapor in the atmosphere can more than double the direct warming from CO2 in a positive feedback. Clouds from increased water vapor can both increase reflected solar energy in a negative feedback, or trap heat in the atmosphere in a positive feedback, depending on the location and type of clouds.

Methane: Methane is another GHG positive feedback. Because it is stored in frozen peat bogs, permafrost, and other stocks under the sea floor, increasing temperatures that thaw these stores also release the trapped methane into the air, causing amplified warming. 

The existence of these feedbacks adds momentum to even small amounts of warming, making climate change challenging to predict. Even more challenging to predict or measure is the potential for these natural systems to become “tipping points,” which can move the Earth’s climate between drastically different stable states. Both ice loss (in the Arctic, Greenland, and west Antarctic) and mass release of methane could become tipping points.

HOW DO RISING TEMPERATURES AFFECT OUR WEATHER SYSTEMS?

The effect of this “global warming” is not, as the name may misleadingly imply, simply warmer temperatures. In fact, higher global temperatures make the atmosphere more energetic, contributing to increased intensity in weather fluctuations and decreased predictability of weather events. This increased intensity and decreased predictability can be found across our entire climate system, from wind, clouds, and storms to heat waves and more.  

As an example, warming air boosts evaporation and increases water vapor in the atmosphere. This can worsen the length and severity of droughts while at the same time leading to heavier, more dangerous rain and snowstorms. 

Extreme weather events are classified as such if they are unlike 90-95% of similar weather events in the same area. Scientists are learning to estimate how increased GHGs can make an event more severe or more likely to happen, a process referred to as “extreme event attribution.” 

WHAT ARE SOME OBSERVABLE EFFECTS OF CLIMATE CHANGE?

Extreme global temperatures  

-  The planet’s average surface temperature has risen about two degrees Fahrenheit since the late 19th century. Most of the warming occurred in the past 35 years, with 16 of the 17 warmest years on record occurring since 2001. 2016 was the warmest year on record; eight of the 12 months were the warmest on record for those respective months.  

-    In 1950, record lows and record high temperatures over the course of the year were equal. Over the last decade, record high temperatures happened twice as often as record low temperatures.

Many of the deadliest heat waves in recorded history have happened since 2000. Heat fatalities in the period 2000-2010 were up more than 2,000% compared to the previous decade, according to the World Meteorological Organization. Heat waves are one of the deadliest kinds of natural disaster in the US and kill more people in cities annually than hurricanes, lightning, tornadoes, and floods combined.  

-    In North Africa and the Middle East­—home to over a half billion people—the average annual number of extreme high temperature days has doubled since the 1970s.  

-    Hundreds of millions of people earn their livelihoods working outside, and billions more depend on goods and services that result from that labor. In high temperatures the human body expels heat by dilating blood vessels and increasing blood flow to the skin to release heat, while sweating cools the skin. At temperatures higher than the body, blood at the skin will not release heat, and at high humidity sweat cannot evaporate and the skin will not cool. As a result, heat exhaustion and heatstroke can occur, triggering seizures and convulsions, and can even be fatal without treatment. Even in less-than-fatal temperatures, working hours and productivity can drop. 

 Oceans and sea level rise

-    The oceans have absorbed much of the world’s increased heat, with the top 700 meters of ocean showing warming of 0.302 degrees Fahrenheit since 1969.

-    Glacial melt as a result of this warming has raised global sea levels by about eight inches in the last century. The rate in the last two decades, however, is nearly double that of the last century. 

-    The Greenland and Antarctic ice sheets have decreased in mass: Data from NASA's Gravity Recovery and Climate Experiment indicate that Greenland lost 150 to 250 cubic kilometers (36 to 60 cubic miles) of ice per year between 2002 and 2006, while Antarctica lost about 152 cubic kilometers (36 cubic miles) of ice between 2002 and 2005. 

-    Increasing uptake of carbon dioxide by the oceans by 2 billion tons per year has caused the acidity of surface ocean waters to increase by about 30% since the industrial revolution, reducing carbonate in the water that marine organisms such as coral and plankton use to build their shells and skeletons. Additionally, acidic water causes their shells to dissolve and damages corals, which provide habitat for millions of species. 

-   The Great Barrier Reef, the world’s largest single structure made by living organisms and a World Heritage Site, is bleaching at an alarming rate. As of 2016, 30% of the corals had died. The Great Barrier Reef Marine Park Authority (GBRMPA), which compiles a report on the reef every five years, most recently rated the status of the reef as “very poor,” and stated that was “largely driven by climate change.” By the end of 2017, 50% of the corals were dead along with two-thirds of the entire reef.  

-    A 2019 NOAA study identified 40 different US locations facing accelerating high tide flooding trends. Miami, FL, a city especially vulnerable to flooding due to its construction on top of porous limestone and its location just above sea level, is forecast to spend $400 million to defend its stormwater systems over the next 20 years. 

Additionally, the Army Corps of Engineers is currently considering a multi-billion-dollar plan to build a 10-foot sea wall by the Florida east coast. 

Many of these solutions will prove to be short term in nature. After Hurricane Katrina, the Army Corps of Engineers invested $14 billion to construct levees and floodwalls in New Orleans, a project only expected to provide sufficient protection for another four years.

-    In NYC, an estimated $4 billion in property value will be subject to tidal inundation by 2100, as well as other coastal areas. 

-   The Rhode Island Coastal Resource Management Council estimated that sea level rise would flood 605 buildings six times a year. Efforts to build sea walls or move structures are only temporary solutions. Also in Rhode Island, the warmer water has plummeted the lobster catch by 75% in the past twenty years.  

 -   Mumbai, India—the financial capital of the country, with a population of more than 20 million people—has by some estimations the largest concentration of people at risk from sea level rise. The rise, paired with increasingly extreme weather events, threatens the entire city.  

Extreme weather events

-   The intensity, frequency, and duration of North Atlantic hurricanes, as well as the frequency of the strongest (Category 4 and 5), have all increased since the early 1980s. 

-    NOAA has concluded that on a global scale, there will be an increase in tropical cyclone precipitation rates, cyclone intensity, and frequency of “very intense” tropical cyclones. 

-    While average annual precipitation has not changed, India’s Meteorological Department has confirmed that the seasonal reliability of the annual monsoons has increasingly changed to periods of drought followed by intense precipitation and floods. As a result, while Mumbai flooded for weeks at a time in 2019, reservoirs supplying drinking water to the southern city of Chennai dried out.

-   In 2018, the southern coastal state of Kerala, one of the most densely populated in India, experienced the worst floods in almost 100 years, affecting an estimated 5.4 million people. Between June 1 and August 28, cumulative rainfall was more than 42% higher than typical averages. 

-    Wildfires in California have increased fivefold since 1972—a result of outdated electrical utility equipment and hot, dry, and windy conditions. Increasingly fluctuating temperatures reduce the lifespan of asphalt, add stress to expansion joints on bridges, and cause bucking of railways, among other effects.  

Economic impact 

-   Across the US, insurance premiums are rising in areas vulnerable to changing climate, and certain areas are uninsurable. In California, where wildfires are increasingly frequent and damaging, the state banned insurance companies from dropping policies of customers in or near recent fire-affected areas. California insurers filed for 80 rate increases in 2018, more than double that of 2015.   

-   By 2030, global fish demand is expected to increase by 20% or more, while “fish populations in the oceans are being depleted due to destructive fishing practices, inadequate policies and climate change.” Fish is the primary source of protein or income for more than three billion people globally.

-   The Australian Great Barrier Reef, one of the most biologically diverse places in the world, which has suffered severe bleaching (as described above), supports 64,000 jobs and contributes $6.4 billion annually to Australia’s economy.

WHAT IS THE CURRENT GOAL FOR STEMMING CLIMATE CHANGE? 

The most ubiquitous global climate change goal was set at the Paris Accord on climate change, which set the goal of limiting the global temperature increase to below two degrees Celsius, while pursuing efforts to limit the increase to 1.5 degrees. Currently, 197 states and the European Union have signed this agreement with “a collective aim to strengthen the global response to the threat of climate change by keeping a global temperature rise this century well below two degrees Celsius above pre-industrial levels and to pursue efforts to limit the temperature increase even further to 1.5 degrees Celsius.” Eight signatories have not backed the deal, including large oil-exporting nations such as Turkey.

Specifically, the agreement does the following: 

-       Sets the goal of limiting global temperature increase to below two degrees Celsius, while pursuing efforts to limit the increase to 1.5 degrees. 

-       Establishes the concept of Global Peaking, which means that no country that is a party to the agreement should see their CO2 emissions increase after signing the agreement. 

-       Commits all parties to prepare, communicate, and maintain a nationally determined contribution (NDC) and to pursue domestic measures to achieve it. Parties must communicate their progress on achieving their goals every five years. 

-       Encourages countries to improve “sinks and reservoirs.” These are places like forests and large waterways that help to absorb harmful emissions. 

-       Develops a framework for cooperation between parties. This section is about opening the market so things like renewable energy tech and companies can easily cross borders.  

-       Creates a fund to help developing countries deal with losses associated with climate change (hurricanes, rising sea levels, etc.).  

-       Provides finance, technology, and capacity-building support for developing nations. 

-       Creates financing of a public awareness campaign on the dangers of climate change. 

-       Requires all parties to be transparent in regards to their emission levels.  

-       Provides that a “global stocktake” will take place in 2023 and every five years thereafter, to assess collective progress toward meeting the goals of the agreement.  

WHY 1.5 DEGREES?

The Brookings Institute provides a brief history of this goal. “The origins are in the original international treaty on climate change, the 1992 Framework Convention on Climate Change. This treaty (which was negotiated under the George H.W. Bush administration), recognized the importance of climate change and set up a process for the international community to begin to address it. The core principle of the international approach to climate, formally embedded in that agreement, was ‘to avoid dangerous anthropogenic interference in the climate system.’”

“Consensus was built around the two-degree goal but there were concerns that even two degrees was too high. This led to the embedding of a 1.5 degree goal at the beginning of the landmark 2015 Paris Agreement: ‘Holding the increase in the global average temperature to well below two degrees above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5 degrees above pre-industrial levels.’”

The Intergovernmental Panel on Climate Change (IPCC) provides the following estimates of the impact and risk associated with the various degrees of warming below and above 1.5.

WHAT ARE PREDICTED OUTCOMES AT OTHER LEVELS OF CLIMATE CHANGE? 

Here is a breakdown of some of the predicted outcomes if we reach certain levels of warming by the year 2100: 

Two Degrees

This is a tipping point that we are almost certain to reach, and by many estimates can be considered a “best-case scenario.” Predicted outcomes would include: 

-       Up to 99% of coral reefs would be wiped out.

-       Collapse of the planet’s ice sheets.

-       Flooding of hundreds of the world’s largest coastal cities, including Miami, Dhaka, Shanghai, and Hong Kong. 

-       400 million people will suffer from water scarcity.

-       Major cities on the equatorial band will be unlivable due to heat.

-       Heat waves in the northern latitudes could kill thousands. 

-       In India, heat waves would increase by 32 times in frequency and last nine times as long, resulting in exposure of 93 times more people. 

Three Degrees

-       Southern Europe would be in permanent drought.

-       Average drought in Central America and the Caribbean would last 19 and 21 months longer respectively.

-       Average drought in northern Africa would last five years or longer. 

-       Areas burned by wildfires would double in the Mediterranean, and sextuple or more in the United States. 

Four Degrees (“Hothouse Earth”) 

-       Eight million more cases of dengue fever would occur in Latin America annually.

-       Global food crises would arise annually. 

-       The world would see 9% more heat-related deaths. 

-       In India, temperature increases could contribute to more than 1.5 million deaths annually, surpassing infectious diseases. 16 of India’s 36 states and union territories would become hotter than today’s hottest state (Punjab) with an average annual summer temperature around 90 degrees Fahrenheit.

-       Globally, damages could pass $600 trillion—more than twice the wealth that exists in the world today. 

Eight Plus Degrees 

-       A third of the Earth would be unlivable due to direct heat. 

-       Humans at the equator and the tropics would not be able to move outside alive. 

-       Oceans would swell to 200 feet higher, flooding two-thirds of the world’s major cities.

-       No land would be capable of efficiently producing food we eat today.

-       Forests would be roiled by firestorms.

-       Tropical disease would sweep as far north as the Arctic. 

-       Today’s “intolerable” drought and heat waves would be the existence of all human life.

Though the models cannot predict where we will fall on this scale, if we continue industrial growth on the scale we have over the past 30 years, by the end of the century vast swaths of the Earth will be unlivable by the standards we have today.

WHY DID PRESIDENT TRUMP WITHDRAW FROM THE AGREEMENT?

The reasons provided by the president were not specific. He made general references about the cost of the agreement to the US, such as “The bottom line is that the Paris Accord is very unfair at the highest level to the United States.” He claimed that the agreement, if implemented, would cost the US $3 trillion in lost GDP and 6.5 million jobs. He added that it would “undermine our economy, hamstring our workers,” and “effectively decapitate our coal industry.” He provided no evidence to back up his claims. 

WHAT IS THE PRACTICAL IMPLICATION OF THE WITHDRAWAL?  

The US’s process for withdrawal from the Paris Agreement began in 2019, and will be complete at the end of 2020, which will mark the end of a one-year waiting period. Of the 197 countries in the agreement, no other country has followed the US’s lead, and the agreement remains in place. Finally, several states, municipalities, and major industrial companies (like General Motors) have renewed their commitment to the agreement despite the president’s actions. 

WHO ARE THE LARGEST GLOBAL EMITTERS OF GHG FROM FOSSIL FUEL COMBUSTION AND INDUSTRIAL PROCESSES?

In 2017, the global average of per-capita CO2 emissions was 4.8 tonnes. In comparison, the top populous countries for per-capita emissions are the United States, Australia, and Canada at 16.2, 17 and 15.6 tonnes respectively. “Populous” is relevant, because the largest per capita CO2 emitters are the low-population countries that are major oil producers, with #1 being Qatar at 49 tonnes, followed by Trinidad and Tobago at 30 tonnes. 

Looked at another way, in 2018, the measurement of primary energy consumption per capita for the US was 294 gigajoules. For Canada, it was 390.3 gigajoules, compared to 76.0 gigajoules per capita globally. This means we consume, per person, nearly four times the global average of primary energy, and Canadians consume over five times the global average (source). China, the top consumer of fuel by country, consumes only 96.9 gigajoules per capita.  

WHY IS US ENERGY CONSUMPTION SO HIGH?  

Many factors contribute to our high emissions, but all are related to our reliance on and acquisition of cheap energy. 

Geography

The USA has a relatively low population density relative to other countries such as Japan or those in Europe. As a result, our homes can be larger (aided by subsidized mortgages), suburban communities are more spread out, and people live longer distances from workplaces. As you can read about in our Infrastructure Research, “mass transit is less developed, and we drive farther for commuting and recreation.”

Consumption

Americans have also enjoyed a history of cheap energy compared to the Europeans and Japanese. As a result, our homes are larger, our cars are bigger, we consume more water, and we have a habit of using disposable items, such as plastic bags, individual-serving-size packaging, paper products, cleaning products, and razors, more than our counterparts. All of these factors contribute to our being one of the largest emitters of carbon per capita among developed nations.   

WHAT DOES US ENERGY CONSUMPTION LOOK LIKE TODAY? 

As can be seen in the chart above, as of 2018, our largest energy sources are petroleum (crude oil) and natural gas, followed by coal, which has declined over the past decade. Coal-burning plants are the largest producers of CO2 in the US, and large numbers of them need to be shut down globally in order to meet the 1.5 degree Celsius warming target.  

According to the EPA, and copied directly from their website, the primary sources of GHG are as follows:

Transportation—28.5%: The transportation sector generates the largest share of greenhouse gas emissions. GHG emissions from transportation primarily come from burning fossil fuel for our cars, trucks, ships, trains, and planes. Over 90% of the fuel used for transportation is petroleum based, which includes gasoline and diesel. Roughly half of such emissions come from passenger cars and light-duty trucks, while the other half come from commercial freight trucks, airplanes, boats, etc.   

Electricity production—28.4%: Electricity production generates the second largest share of GHG emissions. Approximately 68% of our electricity comes from burning fossil fuels, mostly coal and natural gas.

Industry—22%: GHG emissions from industry primarily come from burning fossil fuels for energy, as well as from certain chemical reactions necessary to produce goods from raw materials.

Commercial and residential—11%: GHG emissions from businesses and homes arise primarily from fossil fuels burned for heat, the use of certain products that contain greenhouse gases, and the handling of waste.

Agriculture—9%: GHG emissions from agriculture come from livestock such as cows, agricultural soils, and rice production.

Land use and forestry (offset of 11% of GHG emissions): Land areas can act as a sink (absorbing CO2 from the atmosphere) or a source of GHG emissions. In the United States, since 1990, managed forests and other lands have absorbed more CO2 from the atmosphere than they emit.

WHAT ARE A FEW OF THE MOST EFFECTIVE STRATEGIES FOR FIGHTING CLIMATE CHANGE?

Please see our Resources page for sources that describe climate change efforts, as well as this report on the actions that must be taken to limit global warming to 1.5 degrees, and efforts that have already been completed around the globe. Here are some of the strategies that, when applied globally, can effectively reduce our emissions and aid in fighting climate change: 

Continue to reduce our reliance on coal: The generation of electricity is responsible for 28.5% of carbon emissions in the US. 63.5% of this generation is due to burning fossil fuels, 19.3% is from nuclear, and the balance is from renewables like hydropower, wind, and solar. Coal represents 43% of the fossil-fuel-sourced generation, while natural gas now represents 55%. New natural gas plants, however, emit 50% to 60% less carbon dioxide than does a new coal plant. In addition, the burning of coal contributes to respiratory disease, lung cancer, asthma, and heart attacks. It is also the largest source of toxic mercury contaminating our rivers and streams.   

Coal-generated electricity has been in systemic decline for several years because it is more expensive than natural gas and communities in the vicinity of coal plants have objected to their presence for health purposes. As recently as 1988, coal-fired plants produced 57% of total electricity in the US. In 2017, only 30% of electricity was produced by burning coal. Despite this, due to the greater emission of carbon, coal produces 48% of all fossil-fuel-sourced emissions.   

Continue to promote fuel efficiency and clean mass transportation:   As noted above, transportation of all kinds is the single largest contributor of GHG emissions, at 28.5%. While trucks and cars have become more efficient over time, the number of miles driven by passenger vehicles and trucks has increased 45% since 1990. An increase in less efficient SUVs and small trucks has exacerbated the problem. Federal standards for fuel efficiency and state and federal support for electric and hybrid vehicles are important. According to the Alternative Fuels Data Center, hybrid and plug-in electric vehicles generate roughly half the “wheel to wheel” emissions of gas-fueled vehicles. (The actual amount depends on the original source of electricity.) Mass transportation is an especially cost-effective measure in cities, where cars often sit in gridlock during peak traffic hours. The population density of cities also supports the argument for increased use of public transit. A strong mass transit system comes with many other benefits, including freeing up space in cities (previously devoted to parking) and reducing the “human costs” of pollution like asthma and lung cancer.   

Expand the carbon tax: A carbon tax is a fee charged to businesses and industries based on the amount of their CO2 output. Proposals vary, but typically the funds earned from this tax go to funding renewable energy initiatives. There have been serious objections to carbon tax proposals, but it has been shown to work in areas where it’s been implemented. In 2005, the EU launched the largest carbon tax program in history, and, as of now, all 27 countries are required to participate. In 2010, Japan launched a cap-and-trade program affecting 1,300 companies.    

Continued promotion of renewables: Sources of renewable energy include the sun, wind, rain, waves, and geothermal energy. According to the Renewable Energy Journal, renewables globally now account for 19.3% of total human energy consumption and 24.5% of electricity generation.  They also report that over $288 billion was invested globally in renewables in 2015 and that renewables now account for as much as half of new electrical power generation.   

Change how we consume food: The consumption of beef is the largest contributor to methane emissions. Limiting our beef intake in any way would help lower this output. Standardizing expiration labels would result in less food waste by consumers.  

Change how we manage landfills: When biodegradables are kept separate from non-biodegradables, the biodegradables are allowed to oxidize, preventing them from generating methane.   

Improve standards for buildings: Residential and commercial buildings are responsible for almost 40 percent of U.S. CO2 emissions. New buildings must be designed to be more efficient, and existing buildings must be upgraded to reduce energy waste, with incentives to encourage this. 

HOW HAS THE TRUMP ADMINISTRATION ROLLED BACK CLIMATE CHANGE EFFORTS?  

According to a New York Times analysis based on research from Harvard and Columbia Law Schools, among others, the Trump administration is reversing 100 environmental rules, with 66 completed and 34 in progress as of May 20, 2020. The largest category of these rules is air pollution and emissions, followed by drilling and extraction. Here are a few of the actions that they have taken to roll back previous or prevent future climate change efforts: 

·      In 2015 President Obama implemented the Clean Power Plan, which for the first time set limits on carbon pollution from power plants. In 2017, EPA Administrator Scott Pruitt signed a proposal to repeal the plan. Lawsuits have delayed the administration’s efforts. 

·      Took steps to expand and accelerate the permitting process for oil and gas production on federal lands and loosened offshore drilling safety regulations. 

·      Proposed policy amendments that rescind existing standards requiring oil and gas companies to monitor and repair methane leaks, which could result in an estimatedadditional 5 million metric tons of methane emissions annually. 

·      Issued a Notice of Proposed Rulemaking to freeze the fuel economy and greenhouse gas (GHG) emissions standards for cars and light trucks at 2020 levels through 2026 and revoke the ability of California and allied states to set their own more stringent standards. 

·      Issued a proposal to weaken a requirement that makes companies monitor and repair methane links. This proposal is opposed by oil and gas companies such as BP, Exxon, and Shell as well as scientists and environmental groups. 

·      Loosened restrictions on coal-burning power plants, withdrawing the legal justification for a law that limited mercury emissions from coal power plants.  

·      Dissolved two EPA advisory boards that offer guidance on environmental rulemaking: the Environmental Laboratory Advisory Board (ELAB) and the National Advisory Council for Environmental Policy and Technology (NACEPT). 

·      Blocked State Department written testimony on climate and security by Dr. Rod Schoonover, on the basis that it included “climate alarm propaganda.”

·      Weakened regulations and oversight around air pollution in national parks and wilderness areas. 

·      Approved the Keystone XL pipeline, which was then blocked by a federal judge from moving forward without an adequate environmental review process. President Trump then issued a presidential permit to bypass this ruling, and though initial construction has begun, the project remains tied up in court. 

WHAT ARE A FEW OF THE ARGUMENTS AGAINST CLIMATE CHANGE?  

Some people argue that there is no conclusive evidence that changes in global temperature can be attributed to human causes. They also argue that the Earth has always warmed and cooled, driven by natural factors, like volcanoes and solar energy, thus leading to natural cooling/heating periods. Here are some of the most common arguments against human-caused climate change: 

Argument: “The Earth can naturally adapt to these changes in temperature.” There is evidence that the Earth reacts to changes in the climate/ozone to ensure its own health. The issue, however, is that these natural changes can have drastic negative consequences for the human population. 

Argument: “We are heading into an ice age.” This argument comes from a series of findings in the 1970s that the Earth is headed toward an ice age in about 10,000 years, and suggests that the planet’s increasing temperature due to climate change may actually turn out to be a good thing.  

Argument: “Urban heat island effect.” This theory argues that the increase in global temperatures is the result of the growth of urban areas, and that as more people move to the cities, the world’s temperature will increase, regardless of CO2 emissions. 

COUNTRIES SETTING AN EXAMPLE:

The Climate Change Performance Index (CCPI) is an independent assessment of the progress that each country is making in compliance with the Paris Agreement. The index is published annually by GermanWatch in cooperation with the NewClimate Institute and the Climate Action Network. Based on their most recent findings, no country is doing enough to completely combat climate change (as you will see in the ranking below, where none of the countries included in the index receives a ranking in spots 1-3). The index places a 40% weight on GHG emissions, looking at a country’s current level of emissions compared to a target of below two degrees Celsius, with the balance of the index defined based on the following chart: 

Applying these metrics to each country yields the following scores:

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