Concentrations of carbon dioxide, the main greenhouse gas, reach
the highest levels in at least 400,000 years, as measured in Arctic ice cores.
More than 1,500 scientists from 63 countries, including 110 Nobel Prize winners, issue
a call to action:
“A broad consensus among the world's climatologists is that there is
now a discernible human influence on global climate” that represents
“one of the most serious threats to the planet and to future
generations.”
One hundred and ninety-two nations
agree to the
Kyoto Protocol
to fight global warming. The agreement requires the United States and
other developed countries to cut greenhouse gas emissions, but not
developing countries like China.
1998
The global average temperature of 58 degrees Fahrenheit is
the warmest since reliable records began about 120 years ago.
Industry opponents of the Kyoto Protocol
draft a proposal to spend millions of dollars to convince the public that the environmental accord is based on shaky science.
2000
In the presidential campaign, George W. Bush, the Republican nominee,
promises to cut
carbon dioxide emissions from power plants, while Al Gore, the
Democratic candidate, calls for aggressive climate policies but does not
make climate change a major campaign issue and
mentions it only once in the debates.
2001
Under
strong pressure from conservative Republicans and industry groups,
President Bush says his administration will not seek to regulate
emissions of carbon dioxide from power plants. reversing a campaign
pledge. He also says
he will seek to withdraw
the United States from the Kyoto climate accord and that the United
States will not comply with its emissions-reduction targets.
China
declines to slow the rapid growth of its greenhouse gas emissions.
2002
President Bush proposes a
voluntary plan involving tax credits and other incentives to encourage businesses and farmers to reduce their greenhouse gas emissions.
2003
The Senate
votes 55 to 43 against a bill
sponsored by Senator John McCain, a Republican from Arizona, and
Senator Joe Lieberman, a Democrat from Connecticut, to limit carbon
dioxide emissions by creating a market-driven “cap and trade” program.
Only four Republicans vote yes.
The Republican campaign adviser Frank Luntz
writes a memo
to party officials noting: “Should the public come to believe that the
scientific issues are settled, their views about global warming will
change accordingly. Therefore, you need to continue to make the lack of
scientific certainty a primary issue.”
2004
Climate scientists across the globe
overwhelming agree
that evidence of climate change is clear and persuasive, according to a
detailed analysis in Science Magazine by the science historian Naomi
Oreskes. As she puts it: “Many details about climate interactions are
not well understood, and there are ample grounds for continued research
to provide a better basis for understanding climate dynamics. The
question of what to do about climate change is also still open. But
there is a scientific consensus on the reality of anthropogenic climate
change. Climate scientists have repeatedly tried to make this clear. It
is time for the rest of us to listen.”
2005
At a climate conference in Montreal, the United States and China
refuse to agree to take mandatory steps to reduce greenhouse gas emissions.
Congress passes
an energy policy act
that provides tax and other incentives for some low emissions energy
sources, including nuclear power, hydropower and wind and solar power.
But it also continues large subsidies for fossil fuels.
 |
| A Beijing street this year. Credit Tim Graham/Getty Images |
2006
With its rapid industrialization, China surpasses the United States as the world’s biggest emitter of greenhouse gases.
2007
Congress raises auto fuel efficiency standards for the first time since 1976.
2008
Barack Obama and John McCain, the Democratic and Republican presidential candidates,
endorse limiting greenhouse gas emissions through cap-and-trade legislation.
2009
The House of Representatives passes
a cap-and-trade bill
that would require cuts in greenhouse gas emissions of 17 percent below
2005 levels by 2020 and 83 percent by 2050. Only eight Republicans vote
yes. The bill never receives a vote in the Senate, even though
Democrats control 57 seats and two independents caucus with them.
The American Petroleum Institute, funded by major oil companies, helps
organize and pay for the first Tea Party rallies, including protests against the House-passed cap-and-trade legislation.
President Obama says the United States
will cut greenhouse gas emissions
by 17 percent below 2005 levels by 2020 as part of the Copenhagen
Accord signed by 193 nations. Large developing nations, including China,
also pledge reductions, though they are voluntary.
2010
The International Energy Agency reports that global energy-related emissions of carbon dioxide
hit a high of 30.6 billion tons, an increase of 1.6 billion tons over 2009.
President Obama reaches an agreement with American auto companies to
raise fuel efficiency standards to 54 miles per gallon by 2025, the largest emissions-cutting action of his presidency.
2011
More than half of all carbon dioxide emissions from fossil fuels combustion since the Industrial Revolution began in 1751
have occurred just since the mid-1980s, according to a study by scientists for the United States government.
Greenhouse gas emissions in the United States decline slightly, but China’s
have increased by about 170 percent since 1999.
2012
In
his acceptance speech to become the Republican presidential nominee,
Mitt Romney mocks President Obama’s climate efforts: “President Obama
promised to slow the rise of the oceans and to heal the planet. My
promise is to help you and your family.”
2013
Scientists report that concentrations of carbon dioxide
reached a record 400 parts per million
in the atmosphere, the highest levels in at least three million years,
before human beings evolved, and that global emissions rose by 60
percent between 1990 and 2013.
In his second Inaugural Address, President Obama calls climate change the
leading issue of our time.
“We will respond to the threat of climate change, knowing that failure
to do so would betray our children and future generations.”
More than 60 percent of all carbon dioxide emissions come from
six nations:
China, 30 percent; the United States, 16 percent; India, 6 percent;
Russia, 5 percent; Japan, 4 percent; and Germany, 3 percent.
2014
President Obama and President Xi Jinping of China
announce limits
on greenhouse gas emissions; the United States agrees to cut emissions
by 26 to 28 percent below 2005 levels by 2025; China says it will begin
scaling back emissions before 2030. The agreement sets the stage for a
global climate deal.
A United Nations
study finds that even if global greenhouse gas emissions are cut to the
level required to keep temperature rise below 3.6 degrees Fahrenheit or
2 degrees Celsius, the cost of climate change adaptation in developing
countries is likely to reach two to three times previous estimates of
$70 billion to $100 billion per year by 2050
2015
The Paris climate accord
is approved by 195 nations,
including the United States, marking the first time that all major
nations pledge to make emissions reductions to limit the global average
temperature increase to less than 3.6 degrees Fahrenheit.
The
Republican-controlled Congress votes to phase out tax credits for wind
and solar energy by 2020; various tax incentives for fossil fuel
production remain. President Obama signs the bill, citing support from
the renewable energy industry.
2016
2016 is the
warmest year on record, the third consecutive year that a global annual temperature record has been set, and the 40th consecutive year that annual temperatures have been above the 20th-century average. The five warmest years have all occurred since 2010.
James Hansen and other scientists publish research finding that current global temperatures are the
highest in at least 115,000 years, when sea levels were 20 to 30 feet higher than today.
Nearly all of the 16 Republican presidential hopefuls
deny the science of climate change, and none support the Paris climate agreement. Donald Trump pledges to “cancel” American involvement in the Paris accord.
Not a single question on climate change is asked by moderators in any of the four presidential or vice-presidential debates.
The United States joins with 189 other countries
to phase out hydrofluorocarbons, gases used as refrigerants, a move that will stave off nearly a degree Fahrenheit of warming by 2100.
Mr.
Trump is elected president following a campaign in which he called for
more fossil fuel drilling, fewer environmental regulations and vowed to
pull the United States out of the Paris climate accord. “Regulations
that shut down hundreds of coal-fired power plants and block the
construction of new ones — how stupid is that?”
Mr. Trump asked during the campaign.
2017
Following up on his campaign promises, President Trump
signs an executive order
directing his administration to undo regulations to cut emissions from
the electric power sector; orders the resumption of the federal coal
leasing program; says he will seek to weaken fuel economy standards for
cars and light trucks; and proposes to cut the budget of the
Environmental Protection Agency by 30 percent. He also says he will
withdraw the United States from the Paris climate accord.
Hurricane Harvey unleashes 50 inches of rain,
the largest rainfall
in United States history, paralyzing five million in Houston, killing
30, with a price tag of at least tens of billions of dollars to federal
taxpayers. Multiple peer-reviewed studies find that Hurricane Harvey was
made as much as 40 percent larger and more intense because of warming
Gulf of Mexico waters tied to the changing climate.
More than
30 leading climate science and policy experts,
including Nobel Prize winners, say that limiting global temperatures to
below 3.6 degrees Fahrenheit will require removing fossil fuels from
the global energy system by 2050, reducing emissions of super greenhouse
gas pollutants like HFCs, methane and black carbon rapidly by 2030, and
extracting carbon dioxide directly from the atmosphere.
 |
| A wildfire raging through Paradise, Calif., in November. Credit Noah Berger/Associated Press |
2018
Concentrations of carbon dioxide in the atmosphere reach 410 parts per million, the
highest level in at least three million years
President Trump insists coal
is the key
to the country’s energy and economic future and orders Energy Secretary
Rick Perry to take immediate steps to prevent market shutdowns of coal
plants.
The Trump administration says it will
roll back fuel economy standards
set by the Obama administration for cars and light trucks, a move that
would increase greenhouse gas emissions in the United States by an
amount greater than many midsize countries put out in a year.
In another move to undo the Obama climate legacy, the Trump administration proposes
letting states set their own coal emissions regulations,
upending rules to reduce carbon dioxide emissions from coal-fired power
plants. Many experts say this will cause greenhouse gas emissions from
the power sector to begin rising for the first time in decades.
After falling for more than a decade, carbon dioxide emissions in the United States are
set to rise by 2.5 percent in 2018. Global emissions grew by 1.6 percent in 2017 and will increase by about 2.7 percent in 2018.
Go. Jerry Brown of California
signs legislation requiring that 100 percent of the state’s electricity come from carbon-free sources by 2045.
Thirteen federal agencies present
the starkest warnings to date
of the consequences of climate change for the United States, predicting
in a report that if significant steps are not taken to rein in global
warming, the damage will knock as much as 10 percent off the size of the
American economy by century’s end. The report warns of devastating
effects on the economy, health and the environment, including record
wildfires in California, crop failures in the Midwest and crumbling
infrastructure in the South.
An international team of scientists
finds
a growing likelihood that runaway warming could destabilize the entire
global climate system and lead to a “Hothouse Earth” that in the long
term will push global average temperatures to seven to nine degrees
Fahrenheit warmer than preindustrial temperatures, with seas 60 to 200
feet higher than today. “Humanity is now facing the need for critical
decisions and actions that could influence our future for centuries, if
not millennia,”
the scientists write.
*Paul Bledsoe is strategic adviser at the Progressive Policy Institute
and a lecturer at American University’s Center for Environmental
Studies. He served on the White House Climate Change Task Force under
President Bill Clinton.
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