Global Climate Change: Exam 1

*If someone were to argue that the recent increase in carbon dioxide was primarily due to non-anthropogenic sources, what evidence would you provide to refute their hypothesis?

-It is a known fact that fossil fuels, cement, and deforestation are sources of carbon dioxide emission. That is undeniable. The usage of the fossil fuels, the production of cement, and the deforestation have increased in the past 150 years significantly since the industrial revolution. It happens that the increase in CO2 levels in the past 150 years have skyrocketed significantly faster than they ever have in comparison to the history of the world. Scientists studying the history of earth's climate change are able to determine temperature changes from gas bubbles in the ice containing isotopes of O2. There is, of course, natural climate change that occurs with periods of warming and cooling, but the warming that has occurred over the past 150 years has happened so quickly, there is no way that it is natural. This change has to have happened from some unnatural cause and our CO2 emissions are very unnatural.

*Some might contend that the theory of global warming due to anthropogenic carbon dioxide production is a new theory that must receive more study before acceptance. What could you say concerning the history of this theory?

-The theory of global warming is no longer able to be considered "new." Jean-Baptiste Fourier recognized the warming effect of gasses in the atmosphere and attributed the effect to a greenhouse gas in 1827. -Even Svante Arrhenius thought the CO2 was warming the global temperature but he thought it was good because he wanted it warmer. -Guy Callendar proposed the earth was warming due to anthropogenic CO2 increase from fossil fuels in 1938 but this was ignored. Charles Keeling started measuring global co2 levels in 1958 which gave a lot of info. -This history of this theory is really telling to how long we are taking to accept it. I think that this history has been around so long and the theory has not changed much since then. Back then and still today we know there is a correlation between CO2 levels and temperature and we still ignore it.

Know the details in the movie notes for Dimming of the Sun. These will be covered in multiple choice questions. Know the negative feedback that aerosols play in our current climate.

Aerosols

What is the anthropocene?

The current geological epoch since the late eighteenth century which has had huge anthropogenic effect on the environment.

*Explain the source and history of the "Hockey Stick Controversy". (I recommend that you read the Wikipedia article on this topic)

The temperature changes over time have been decreasing but in last 150 years there have been extreme increases in temperature which are consistent with increasing greenhouse gas levels (Data discovered using proxy indicators) -An economics professor and a math student who works for a gas company worked together on a statistical ground to publish Energy and Environment in 2003. Said Hockey stick method was random and the reconstruction was wrong. They were funded by the oil and coal industry which made them biased. Also, they had a low impact factor and H-index making their paper less than significant. -Congressman Joe Barton (against GCC) called Mann to present all of his data and source code, archives of all data for his scientific publications, and identities of past and present collaborators. Mann did it though and was found to be right and his data was able to be repeated (IMPORTANT).

Define the troposphere and stratosphere, and describe the fundamental differences between the two layers. What have been the warming/cooling trends in these two layers over the past 30 years (the length of the satellite record)?

-Troposphere: 85-90% of the mass of atm, warms by convection of warm earth. If radiation from earth is trapped it warms more-->transfers heat into atm. Cold air on warm air is unstable so constantly mixes. -Stratosphere: Warms based on solar radiation and ozone trapping heat. Closer to the sun--> warmer it is. Very stable but fierce winds and has been cooling recently. -Troposphere has been WARMING -Stratosphere has been COOLING -Usually there is a reradiation back from the earth into the atmosphere. With all of the greenhouse gases in the troposphere, the radiation gets trapped in the troposphere and doesn't make it to the stratosphere, so there is warming in the troposphere and less radiation in the stratosphere so it is cooler.

*There are two low probability but high consequence possible future outcomes from anthropogenic global warming. Explain what these are and what the effects would be.

1). Shutdown of thermohaline circulation. -Oceans reduce the extremes of atm temp and reduce the rate of climate change because a large amount of heat is needed to warm the oceans slightly. The oceans redistribute heat in climate system through internal circulation. -Deep water formation occurs at poles because warm water arives and it evaporates making water cooler and sea ice forms which makes the sea colder and saltier-->deep water current forms & drives system. Changes are slow but if the bottom waters warmed the warming will continue no matter what we do. 2). Release of methane clathrates from ocean. -Methane is in sediment by high P and cold T. Methane release is thought to be responsible for global warming that caused the end-permian mass extinction because it warmed too fast and the methane was released from the ocean.

*Know the seven positive feedback loops well enough to explain how they work. What are the two tipping points we discussed in class?

1. Ocean circulation feedback 2. Ice-albedo feedback 3. Water vapor 4. Acidified ocean feedbacks 5. Warming and methane clathrates 6. Permafrost and soil feedbacks 7. forest loss feedbacks Tipping Points: 1. Once feedback loops kick in we will reach the point of no return and cant do anything about it. 2. We will lose arctic ice and there will be runaway climate change and we just let it go.

What are the sources of the various greenhouse gases, and what is the difference in today's level of each in the troposphere and the levels 150 years ago?

CO2 -Listed above -Increased 31+/-4% Methane -Natural: Wetlands, termites, ocean sediments, permafrost melting -Human: Leakage from coal mines, belching by cattle, rice paddy fields, landfills, burning wood, waste treatment -Has doubled since 1800 (unprecidented for 650,000 years) -151+/-25% Nitrous Oxide -Human: Increased fertilizer use for agriculture -Has increased 17+/-5% since industrial revolution CFC's -Human: Refrigerants and aerosols -Has increased 1ppB (BILLION--less than MILLION) due to the heavy usage in the 1980s. Will take 100 years for CFC's to make any decline. Ozone -Increased by 35%+/- 15% in past couple hundred years -Produced by car smog and in upper atm by jet planes (nitrogen oxides for both)

*How does the philosophical theory of knowing called empiricism relate to the debate about climate change? Why are scientists almost 100% on one side of this controversy, even when they are not necessarily trained as meterologists or paleoclimatologists?

Empiricism: A theory of knowledge which asserts that knowledge arises from experience. -Experience and evidence are of greater value than innate ideas, intuition, or revelation. -Empiricism agrees with global climate change because there is so much evidence to support it and people are experiencing its effects everywhere. -Scientists are almost 100% on the side of this controversy even if they are not trained in the subject because scientists, although cautious, trust science. There (generally) is no politics involved in the science.

What are the five primary greenhouse gases in our atmosphere that have increased over time due to human activity? List them in decreasing order of importance. What greenhouse gas is not directly effected by human activity, but still plays a significant role in anthropogenic climate change?

Most significant--> Least significant 1. Water Vapor 2. Carbon Dioxide 3. Methane 4. Nitrous Oxide 5. CFC's We are not pumping water vapor into the atmosphere directly but it has a very significant role in anthropogenic climate change

What are the natural sources of carbon dioxide to the atmosphere, and how is carbon dioxide removed from the atmosphere?

Natural sources of CO2 to the atmosphere include: -Animals -Fire -Rotting wood -Decomposition of organic materials in the soil & elsewhere. Carbon Dioxide is removed by: -Ocean sink: -Algae -Plankten die and take carbon to sediment -Calcium carbonate formers remove a lot -CO2 dissolves in seawater but not very soluble -Photosynthesis of plants

What observations over the last 100-150 years indicate that the climate has warmed during that period of time? Can you list and briefly explain the 1) nine weather indicators and 2) seven physical indicators, 3) four biological indicators, and 4) one economic indicators - of climate change form Table 4.1. Recite these to a friend, and have them ask you for clarification if they do not understand your explanation of them.

Nine weather indicators: 1). Global mean surface Temp 2). Northern hemisph surface temp 3). Diurnal surface temp range 4). Hot days/heat index 5). Cold/frost days 6). Continental precip 7). Heavy Precip events 8). Drought 9). Tropical cyclones/intense extratropical storms Seven Physical Indicators: 1). Global mean sea level 2). duration of ice cover of rivers and lakes 3). arctic sea-ice extent and thickness 4). non-polar glaciers 5). Snow cover 6). Permafrost 7). El nino events four biological indicators: 1. Growing season 2. Plant and animal ranges 3. Breeding, flowering, and migration 4. Coral reef bleaching Economic indicator: 1. Weather-related economic losses.

Explain the study by Naome Oreskes on the consensus behind climate change.

She analyzed 928 abstracts for scientific journals listed in the ISI database with the keywords climate change and observed that none disagreed with the consensus of GCC but some 25% did not take a view.

Explain what happened during the PETM and why we care about this ancient event today.

There was a very high increase in CO, and probably methane, which caused a major extinction event, especially in marine life with the acidification of the oceans. The acidification today is worse than it was during the PETM, as well, and our CO2 is rising at an incredible rate in comparison to the PETM which was in itself, pretty quick. This sets a great example of the negative impacts of what can happen with continued CO2 emissions. Biodiversity is in great danger at the rate we are going.

Why is the ocean thermohaline circulation called an inertial effect? What is the significance of its effect on climate change and mitigation effects?

this is because it takes the ocean a long time to warm. this actually helps with cooling because it redistributes heat through internal circulation.