Historical perspective on Climate Change

How has agriculture contributed to human survival?

Humans became a dominant species on Earth in a time of narrow climatic range, especially since the Neolithic revolution and rise of agriculture. Agriculture has allowed the exponential population increase of the past 10,000 years, relying upon a few crops adapted to the current climate, like wheat, rice and corn.

What evidence proves that Global Climate Change was not caused by natural causes?

If current global warming was caused by a more active sun, then scientists would expect to see a warming at the surface of the atmosphere AND the lower parts of the atmosphere (inner core of the Earth) but greenhouse gases capture heat in the lower atmosphere, so because the temperature is higher at the core, we know it's not coming from a more active sun. Also solar irradiance changes cannot reproduce last century's observed temperature trend without including a rise in greenhouse gases.

When did the first step of burning coal begin?

In 1712 when Thomas Newcomen invented a coal-burning steam engine which drained the water from coal mines, this replaced a team of 500 horses walking in a circle and allowed the profitable mining of coal.

State the quantitative increase in CO2 emissions over the last century

In the 18th century CO2 emissions were around 3 to 7 million tons per years, 19th century 54 million tons per year, currently over 8000 million tons per year.

When did the Industrial revolution begin?

The Industrial revolution began in Britain in the 1700s with the transition from a worker-based cottage industry to a machine-based economy, with the growth of factories and mass production.

Which country met its UNFCCC target?

The UK

What did air in polar ice show?

The beginning of growing global concentrations of carbon dioxide and methane.

What is the Kyoto Protocol?

The first international treaty to set legally binding emission cuts for highly industrialized nations, it was signed by 178 countries and came into force in 2005.

How does global climate change affect agriculture?

The full impacts of contemporary global warming on food production remains to be seen but in recent years food shortages have become increasingly common (the impact of the summer of 2012 on U.S. corn, soy and other food production). Like other species that have come and gone before us, we too have our vulnerabilities.

Who were the Anasazi?

The group which dominated a territory in the American Southwest larger than any European principality of the time, but by the end of the 13th century their civilization disappeared. The long drought which lasted decades that occurred in 1280 may have been what caused them to abandon their land.

What is the Holocene?

The holocene is a geological epoch which began at the end of the Pleistocene (12,000 C years ago) and continues to the present.

What was the industrial revolution based on?

The industrial revolution was based on the massive growth in energy consumption, largely through the burning of coal, a fossil fuel.

What is the Intergovernmental Panel on Climate Change (IPCC)?

The leading international body for the assessment of climate change. It's job is to review and assess the most recent scientific, technical, and socio-economic impacts. Thousands of scientist from all over the world contribute to the IPCC on a voluntary basis. The IPCC warned that only strong measures to stop greenhouse gas emissions would prevent serious global warming.

What did Andrew Curry discover about climate change and ancient civilizations?

The rise and expansion of the Roman Empire & Medieval period was characterized by mild, warm summers and wet weather - two things essential for large-scale agriculture. But when climate began to decline barbarian invasions and political turmoil occurred which contributed to the fall of the Roman Empire.

Explain solar variations affect on climate change.

The sun is a source of energy for the Earth's climate. Some scientist suspect that a portion of the warming in the first half of the century was due to an increase in the output of the solar system. Scientific studies demonstrate that solar variations have performed a role in past climate changes (a decrease in solar activity was thought to have triggered the Little ice age)

How can the jump in greenhouse gases and nitrous oxide emissions be explained?

These dramatic jumps in greenhouse gas emissions can be explained by the increase of methane emissions from the use of fossil energy (+85%), and particularly gas consumption, and from waste generation (+75%) (landfill sites and waste water). The increase in nitrous oxide emissions is the result of greater use of synthetic fertilizers and manure and of an increase in livestock and farming.

Why were humans able to survive climate change in the past? Why can't they survive now?

They lived in small groups called bands and foraged for food, and were mobile. If weather worsened, they could pick up everything and move because they didn't have many belongings. Now people live in big populations of millions of people and moving them across the globe would be impossible.

Explain how ocean currents affect climate change.

They move vast amounts of heat across the planet. Winds push horizontally along against the sea surface and drive ocean current patterns. Interactions between the ocean can atmosphere can produce phenomena like El nino which occur every 2-6 years. Deep ocean circulate cold water from the poles towards the equator and move warm water from the equator back towards the poles. Without this movement the poles would be colder and the equator warmer. The ocean plays an important role in determining the atmospheric concentration of CO2.

What do dendrochrological (tree ring) and lake sediment records show in the American South West?

They show mega droughts that were intense and persisted for years, reoccurring once or twice every 500 years.

How is Methane (a greenhouse gas) released into the atmosphere?

Through many live stock animals such as cows, pigs, goats, buffalo, etc. As well the process of oil drilling, coal mining, leaking gas pipelines, landfills and waste dumps.

What global deal was agreed upon at the United Nations conference in Cancun 2010?

- An overall target limit of 2 degrees Celsius on temperature rise - Measures that developed and developing countries should adopt - A system to assess how countries are living up to their promises on emissions - The Green climate fund to help developing countries go low carbon - To slow, halt, and reverse the destruction of trees - To help developing countries access low carbon technologies

What happened during the Migration Period?

Climate switched back and forth from cool to dry to and hot and wet almost every decade. These changes had a profound impact on society because climate not only affected agriculture, changes did not last long enough for adaptation.

How did cold snaps and wet summers have an affect on populations?

Cold snaps were found to match historically known famines and wet summers matched the time of the "Black Death", which killed nearly half of Europe in 1347 for humid conditions to help disease spread.

What are the primary factors resulting in climate change over the past millennium?

Variations in solar irradiance and volcanism which account for 40-60% of the temperature variability.

What are some natural causes of climate change?

Volcanic eruptions, ocean current, Earth's orbital changes, and solar variations.

According to James Lovelock what "worse case scenario" awaits us?

the scale of the catastrophe that awaits us will soon become obvious. By 2020, droughts and other extreme weather will be commonplace. By 2040, the Sahara will be moving into Europe, and Berlin will be as hot as Baghdad. Atlanta will end up a kudzu jungle. Phoenix will become uninhabitable, as will parts of Beijing (desert), Miami (rising seas) and London (floods). Food shortages will drive millions of people north, raising political tensions

What were the first discoveries that helped explain recent climate change?

-1753 Joseph Black discovered CO2, John Tydall discovered that some gases block infrared radiation. He suggested that the changes in the concentration of gases could bring climate change. -1827 Jean Baptiste suggested an atmospheric effect kept the Earth warmer than it would be otherwise (Greenhouse effect) -1896 Svante August Arrhenius proposed that increased CO2 emission will enhance the greenhouse effect and cause global climate change -1938 G.S Callendar argued that CO2 greenhouse global warming is underway

What is the Younger Dryas (The Big Freeze)?

A geologically brief period of cold climatic conditions and drought which occurred between 12,800 and 11,500 years before the present. The Younger Dryas marked the end of High Paleolithic culture. In Europe there was a big depopulation with people still surviving in coastal regions.

Why is the most dominant species most vulnerable to global climate change?

Because their dominance was based on their particular successful adaptation to the existing conditions. The earth will always survive catastrophic change like sudden warming; so, too will life. • There have been past extinctions when 90% of all species died; the few that were left then repopulated the planet with new and emergent life forms. This was the case with the rise of mammals, after the extinction of the dinosaurs (birds survived as direct ancestors of dinosaurs).

Explain how Earth's orbital changes affect climate change.

Earth makes a full orbit around the sun yearly. It is tilted at an angle of 23.5 to the perpendicular plane of its orbital path. Changes in the tilt of the Earth can lead to small, but climatically important changes in the strength of the seasons. More tilt means warmer summers and colder winters; less tilt means cooler summers and milder winters.

What are some early warnings (1950s+) of global climate change provided to us?

In the 1950s CO2 measurements were taken on a mountain top in Hawaii, these measurements confirmed that levels of CO2 in the atmosphere were rising. In 1967 a computer simulation showed that temperatures might increase by 4 degrees Fahrenheit. An ice core in Antarctica revealed a link between CO2 levels and temperature going back more than 100,000 years.

Explain why there is not a simple and direct step from measuring the amount of C02 being trapped in the atmosphere to predicting how hot the planet will get at certain points in the future

Increased heat changes in the planet: ice melts, clouds form, currents change, vegetation changes. How these various changes occur impacts our ability to predict subsequent climate change as these factors impact climate (increasing or decreasing trapped heat) just as they are impacted by it. One reason for studying climate histories is to try and figure out these kinds of relationships.

Why did the Cancun agreement produce only modest results?

It did not require the changes that climate scientists say are needed to avoid dangerous climate change.

How has climate change played a roll in the "peopling" of the Earth?

Modern humans first appears in Africa 200,000 years ago. They move to Asia and Europe relatively fast about 45,000 years ago because of climate similarities in Africa. They reach North Asia and America considerably slower because of the large glacial ice sheets that covered the land. Anders Erickson of the Department of zoology at the University of Cambridge suggested that migration of modern humans out of Africa was blocked until 60,000-70,000 years ago because of the arid climate in Northeast Africa and the Arabian Peninsula. But a combination of lowered sea level and more favorable climatic conditions allowed the migration of humans to the Arabic peninsula and subsequent movement through an otherwise harsh area. Migration to Europe of modern humans may have been slowed by the presence there already of cold-weather adapted Neanderthals from even earlier migration of not fully modern humans out of Africa. Modern humans were able to reach South America about 10,000 years ago.

When did the first Earth day take place?

On April 22, 1970, the first observation of Earth Day took place, a massive series of gatherings and discussions across the U.S. that many credit as the birth of the modern environmental movement. However, recent research by the Netherlands Environmental Assessment Agency, in collaboration with the Joint Research Centre of the European Union, shows that global emissions of greenhouse gases increased by 75% since 1970. Global carbon dioxide emissions rose by approximately 90% during the same period, methane by some 40% and nitrous oxide by 50%.

What is the Anthropocene?

Paul Crutzen argues that the geographic age of Earth in which we now live should be called the Anthropocene because of the significant human role in shaping the bio-geological environment of the planet over the last 150 years. The human driver now far outweighs the impacts of natural drivers of global warming.

How did volcanoes play a roll in past extinction and climate change?

Prior to the land extinction of dinosaurs, volcanoes appear to have caused a massive ocean extinction of life forms. This happened because of extensive volcano eruption in place like India, lasting for 100,000 years. Scientists studying fossils from Seymour island have identified a thick bed of sediment. The amount of layers prove there was two extinctions that killed of species of snails and clams living on the ocean floor. This evidence proves green house build up from volcanoes, leading to a warming environment in the ocean and resulting in species extinction.

What summit occured in 1992?

The Earth Summit where 154 countries signed the United Nations Framework Convention on Climate Change (UNFCCC). It agreed to prevent dangerous warming.

What do we mean when we say the Earth's climate isn't static?

The Earth's climate has changed. 65 million years ago the whole planet was tropical (There were palm trees growing in Antarctica & crocodiles north of Green Land). Over billions of years it has changed because of natural causes.

What are proxies?

Proxies can be use to inform predictions about climate changes in the future. Ice inside glaciers and ice caps in Antarctica and Greenland offer important proxy measures of past climate and other conditions. Bubbles in this ice capture air that was locked into place as much as 800,000 years ago by successive layers of snowfall each year. Also in the ice are dust particles and bits of ancient plants that suggest how wet or dry conditions were on land in ancient times and the kind of vegetation that was growing at the time. Additionally, the composition of the ice itself is impacted by the temperature when it formed. (high temperatures create heavier oxygen molecules, for example). Other proxies include sediment layers on the bottom on seas, tree rings, coral construction.

What inventions quickly lead to the declining air quality in many cities?

Steam engines and other machinery that required coal as a fuel source

Explain how volcanic eruptions affect climate change.

Volcano's throw out large amounts of sulfur dioxide, water vapor, dust, and ash which influence climatic patterns for years through increasing reflectivity causing atmospheric cooling. Tiny particles called aerosols are produced by volcanoes. They reflect solar energy back into space and have a cooling effect on the world.

What do proxies consistently show?

What proxies consistently show is that when C02 levels go up, the temperature on the planet goes up, and vice versa. Further, since all of our measures show C02 is going up now and reaching levels not seen in human history, it is reasonable to expect dramatic changes on the planet.

What is the faint young sun paradox?

When the Earth was young the sun was only about 70% of the energy it omits today. Although the water was not frozen, it was still in liquid form despite predictions. One explanation was that there was more heat trapping CO2 in the atmosphere from volcanoes. As the sun got older and brighter, CO2 levels dissipated and temperatures stayed warm from solar energy.