Climate Science Olympiadđ€Revision Cheat Notesđ± Crash Course Summaries
Causes
greenhouse effect
The Sun is the main source of warmth for the earth and emits UV, infrared rays and visible light in huge quantities.
30% of this radiation is reflected back by the atmosphere,
20% is absorbed by gases in the atmosphere
and the remaining 50% is absorbed by the earth.
When the earth releases absorbed radiation in the form of infrared rays and they are reflected back by the atmosphere, it is called the greenhouse effect.
The greenhouse gasses include water vapour, carbon dioxide, methane and nitrous oxide.
greenhouse gasses
We can measure the global warming potential(GWP) of greenhouse gasses
over periods of time and their carbon dioxide equivalent(CO2e):
How much CO2 would cause the same amount of warming as a certain quantity of another gas.
Fluorinated gasses, released in the production of refrigerators, aerosols and fire suppressants, have the highest GWP,
followed by nitrous oxide and methane.
These measures may be misleading because, while fluorinated gasses, nitrous oxide and methane may have GWPs higher than CO2,
they continue warming the atmosphere for a lesser amount of time.
If the emission of these gasses were to decrease, their warming would also decrease but CO2 would continue to warm for at least 100 years or more.
emissions by source
Emissions can be categorised by source, where they are produced, and end
use, where they are used.
The energy sector produces the most greenhouse gasses, 76% of total
emissions, and includes
producing heat and electricity, building,
transporting fuel and energy used to produce fertilizers and consumer goods.
Next comes farming, accounting for 12â29% of emissions from change of
land use and
farming processes like using farming machinery,
cows, sheep and goats digesting food,
burning of residual crops and breaking down waste by microorganisms.
Thirdly, industry accounts for 5.9% of emissions from producing cement, chemicals and
various other materials like plastic, rubber and human made fabrics,
and is the fastest growing source, having grown by 174% since 1990.
Lastly, 3.2% of greenhouse gasses, especially methane and nitrous oxide,
come from solid waste going to landfills, sorting wastewater and treating
human sewage.
emissions by end use
categorizing Emissions by end use helps us understand the particular
activities or products responsible for emissions and know how to reduce them.
The activities that are worst for the planet occur on roads,
accounting for 11.9% of emissions, including emissions from laying the road,
vehicles on the road and manufacture and distribution of the vehicles;
in buildings, releasing 17.7% of global CO2e emissions from
electricity used in lighting, appliance use (anything plugged into a socket, from toasters to hairdryers),
refrigeration and air conditioning, as well as the heat to warm our houses and workplaces and
any direct fuel use such as gas;
the iron and steel industry, accounting for 7.2% of greenhouse gas emissions,
where COâ is emitted at various points when making steel,
including when fuels are burnt on-site (70%),
and the indirect emissions from electricity and heat used during the production process (30%).
Todayâs food supply chain creates approximately 13.7 billion metric tonnes of COâe,
26% of human greenhouse gas emissions and
It is estimated that the fashion industry is responsible for up to 10% of global greenhouse gas emissions,
more than the emissions produced by international flights or the shipping industry.
emissions by country
Today, China is the biggest emitter of green house gasses,
accounting for 25% of global emissions
but throughout history, USA has released 25% of the CO2 built up in our atmosphere.
Qatar has the highest per capita emissions at 49 tonnes (t) per person,
followed by the major oil producing countries with low populations in the middle east.
Countries that have high incomes and standards of living
tend to have higher per capitas per emissions unless
they have switched to renewable energy.
Consumption based emissions are calculated by subtracting emissions from exported goods and
adding emissions from imported goods to emissions from production.
This shows that the richest half of the worldâs countries (high and upper-middle income)
emit 86% of global COâ emissions while The poorest half (low and lower-middle income)
emit only 14%, the same trend visible within countries.
climate projections
climate models
A prediction is based on the knowledge we possess now
but a projection takes into account how conditions may change in the future.
The climate system is composed of multiple variables and can be influenced by events that are not naturally a part of it, called forcings.
A climate model consists of
equations used to measure individual variables
put together, and their accuracy can be tested by
getting them to project past conditions, data about which can be collected from
bubbles trapped in ice, trunks in trees and fossils and minerals trapped in seabeds.
Though climate models can never be perfectly accurate, they help policy makers make well informed decisions.
water cycle
86% of evaporated water comes from oceans, most of them in the tropics.
Higher temperatures make it easier for water to evaporate and
warmer air holds more vapour, intensifying the water cycle.
Extra water vapour in the air is concentrated to places that are already rainy, making wet places wetter and dry places dryer.
It never rains but it pours leading to
decreased groundwater recharge by almost 70% in Brazil by 2050,
or flooding.
Droughts dry tree branches, making more fuel and
leading to bigger wildfires.
tropical climate
The air in the region in the tropics called the intertropical convergence sone(ITCZ) is hot and buoyant and as is rises it expands and cools, splitting and traveling towards opposite poles, leaving behind deserts like the Sahara and Kalahari. The
cool air travels back to the tropics and completes the circulation called the Hadely cell. The eastward rotation of the earth deflects these winds westward and they become trade winds. The water is cooler and the land warmer here, bringing the
monsoons to South Asia. Because of the intensification of the water cycle due to climate change, and changes to general circulation, itâs predicted that monsoons will impact a larger area, and rainfall will decrease over the Indian Ocean and
increase over India. This could lead to an increase in flooding and landslides. A tropical storm, the most violent on the planet, occurs when water evaporates and cool air replaces it, causing spirals. Global warming provides the atmosphere with
more water vapour, giving storms more water to create heavier rainfall. It is projected by the IPCC that the intensity of tropical cyclones could likely increase if temperatures rise to 2 degrees Celsius.
tipping points
When you balance a glass on its edge, at a certain point the glass will no longer return to its original position but tip over, and this is also the nature of the Earthâs climate. There are 4 main tipping points for the Earthâs climate that scientists say will
fall like dominoes and send the earthâs weather spiralling into chaos. These tipping points are worsening of the El nino effect until it becomes permanent;
loss of rainforests from dehydration due to global warming; the controversial increase in
melting of sea ice resulting in further increases in loss of sea ice; and loss of land ice resulting in higher ocean levels. Researchers are unsure whether these tipping point will ensue by 2100.
global warming
The earth has warmed up before but what is alarming now is the rate at which the warming is occurring. The temperature of 4.5 degree celsius we are predicted to achieve by 2100 was last experienced 5 million years ago, before the existence of
humans and even mammoths! The earth was supposed to be cooling and heading into an ice age but because of greenhouse gasses released into the atmosphere we are warming up at 10 times the rate that warming occurs after ice ages. The
policies in place now are inadequate and even if the pledges made are followed through on, the restriction of rise in temperature to 1.5 degrees hoped to be achieved in the Paris agreement will not be reached. The worst part is, land warms up
more than the earth and regions like the arctic are going to suffer from extreme global warming of up to 7 degree celcius
sea level rise
For the past few thousand years sea levels have been stable but between 1901 and 2018, sea levels rose by 20 centimeters. Surprisingly, melting sea ice does not contribute to increasing sea levels because the extra water just replaces the
space the ice filled earlier. Melting of ice on land in the form of ice sheets in antartica and greenland and glaciers-which are smaller than ice sheets contributing to 21% of total increase- have contributed to 42 % of total sea level rise. Another major
contibution comes from the expansion of water as it heats up due to increasing temperatures. Loss of land ice is also a tipping point though climate models are not accurate enough to predict if this point will be reached with a 2 degree increase in
temperatures, 1.5 degree increase or has already been reached.
open problems
Uncertainty may seem to be a measure of how much we donât know but in science, if there is less uncertainty, the more scientists know, so it is utilized as a measure of how much scientists know. Regarding most facts about climate change,
scientists have very little uncertainty. For example, scientists are 90% sure that deforestation and human activities release excess CO2 that is not part of the natural cycle. The element of uncertainty can never be fully done away with as it is
important for scientists to be frank about the parameters of their knowledge. The facts that scientists are most uncertain of regarding climate change are the ones which will be affected by uncertain, future human choices.
Bonus!!!đđ
The Montreal Protocol and the Paris Agreement both address
global emissions of gases that result in unwanted impacts on
human health and natural ecosystems, but, while on one
hand the Montreal Protocol, an agreement that focuses
on the problem â the emissions of Ozone Depleting Substances
(ODS), identifies what countries should not do, when to phase
out and phase down ODS, and sets up the Multilateral Fund
to provide financial and technical assistance to developing
countries, On the other hand, the paris agreement has
no set solutions since the causes of the climate emergency,
CO2 and other greenhouse gases, are embedded in every sector
of the modern economy, which creates an overwhelming range
of solutions that are difficult to navigate.
why climate matters
people
The unjust and unequal effects of climate change will affect those places most that have contributed the least to this problem, the places that will be least equipped to deal with this problem due to lack of resources. Climate change will make wet
places wetter and dry places dryers, worsening floods- that will destroy water supply points and mix dirty water with clean water, promoting diseases- and worsening droughts. While some places like Europe will get cooler climates that promote
growth of cereal crops, most countries already suffering high levels of hunger will face greater food losses and even Europe would see an increase in crop insects and diseases. Effects of adverse heat including Heatwaves; dehydration, especially
in cities that will house two thirds of the worldâs population; flourishing of bacteria and insects like mosquitoes that thrive in the heat; and air pollution will become commonplace.
economy
Climate change will cost us 2% of global GDP in 2020, nearlt 2 trillion us dollars. These costs are incurred from repairs after storms, treatment of diseases aggravated by climate change and changes to the type of foods consumed. Poorer
countriesâ economies will suffer most as they spend most of their money on food which will become more expensive and increased treatment for diseases will also be expensive. There are entities who will profit from climate change like companies
who respond to diasters and oil companies for whom melting ice will make extraction of fossil fuels easier. It is hard to predict accurately how much climate change will cost us because there are some things like human lives that you cannot put a
price on but we can spend money now to protect us from future, unavoidable consequences and soften their blows.
Extinction
A mass extinction event occurs when over 75% of all species on the planet disappear within a short period of geological time â typically less than 2 million years. the estimated current rate of extinction is 1000 times faster, compared
to background extinction rates. many scientists think we are going through a sixth mass extinction, believing we have entered a new geological epoch named the âAnthropoceneâ, so-called because of the ever-increasing human
influence on Earth. it is becoming harder for species to survive because of climate change and human threats, and extinction is 50 times faster when species are faced with more threaths together, which climate change is aggravating:
direct influences include temperatures rising above a speciesâ level of tolerance, rises in sea level reducing habitat availability and seawater floods making the land and water saltier; indirect effects of climate change by
Altered species interactions are more likely to drive extinctions than direct effects of climate change as, If one species goes extinct, this could lead to the extinction of others, and so on.
There is already much evidence for local extinctions happening due to climate change, where a species no longer lives in a particular area but still exists elsewhere in the world, and As local extinctions build up, species edge ever
closer to global extinction.
life on land
To save themselves from climate change species must be flexible and change their behaviours -to regulate body temperature and save themselves from floods and wildfires- along with making bodily changes eg plants regulating their fluids
to deal with saltier environments after flooding. As 5â10% of land will be lost by 2050 due to 2°C rise in temperature, species will need to migrate not just geographically to cooler places- to which they may face barriers like human made
obstacles and low energy levels and ineffective ways of transport- but they will need to migrate in time to catch up with the species who they depend on who may be nesting, breeding and migrating earlier as due to warmer climates
spring is arriving approximately 2.3 days earlier. Useful genes need to be promoted which may be very slow in species with long life spans, longer time taken to reach maturity and lesser probability of useful genes appearing. Species
will need to move 420 meters per year, 20 times faster than in the climate change after the previous ice age, and thus we must stop warming if we want to preserve the services these species provide to the ecosystem and humans.
ocean life
The ocean has a higher heat capacity than land or air and has absorbed over 90% of the heat energy gained by the planet over the last 50 years. Coral reefs provide a home to fish which contributes to 25% of fish catch in developing
countries and provides revenue to more than 95 countries through tourism. Coral reefs let algae live in them which in turn provide them food but as temperature rises, the algae start producing substances poisonous to reefs so they
kick them out, losing their food source and their colour, which is why it is called coral bleaching. If temperatures rise 2°C above pre industrial levels, 70â90% of corals will be lost and with a 2°C rise almost all of them will be gone.
Interdependent marine species too can mismatch in time and space, upsetting and destroying entire ecosystems, but by far the biggest threat is over fishing despite the industrial chemicals, industrial fertilizers and plastic
we dump in the ocean.
clean energy
number one climate problem
76% of global emissions come from the energy sector but we canât just stop using it as the exigencies of a countryâs development call for at least 5000kWh of energy per person and the real problem is that 84% of our energy comes from
CO2 releasing fossil fuels.
Energy is never created or destroyed, just converted from one form to another and converting energy is almost never 100% efficient-some lost to the surroundings as thermal energy
Electricity is pulling electrons through a wire; Voltage(volts): how strongly electrons are pulled to the other side; Current(ampere): How many electrons pass through the wire in a second. Power(watts)=current x voltage &
Power x time= energy(joules)
fossil fuels
Fossil fuels take hundreds of millions of years to form and the combustion of fuel and oxygen yields CO2, water and energy. In power plants, water is burnt and the steam turns turbines; it can even be used directly in heating. The power
grid constantly needs electricity and inertia of the turbine would keep it spinning until more of the relatively cheap coal can be burnt to match increases in demand. Oil is hard to move away from because, because of its high density it
provides more energy and occupies less space; it is readily available; and it has played a great role in the development of wealthy nations. Moving away from fossil fuels is hard because of the infrastructure, economies and livelihoods
invested in it.
solar power
Solar thermal method of harvesting the sunâs energy uses concentrated solar power by redirecting the sunâs light using mirrors to heat a liquid(water, oil or molten salt) to high temperatures which can be used for heating, stored for later
or boiled and the steam used to move turbines. It is expensive, has huge land and water requirements and can only use direct solar radiation but it has the potential to become more viable when scaled up. When a silicone and phosphorus
crystal with extra electrons is placed next to a silicone and boron crystal with missing electrons, the electrons move and the space where they are touching becomes the depleted region, depleted of holes to fill, but once many holes have
been filled an electric field barrier is created which repels electrons of the n(negative) type giver from the p(positive) type receiver. Solar Photovoltaic Process: light mobilizes electrons from depleted regions; electrons are repelled by negative
ions back into n type; electrons move from n to p type through wires; electrons from wire fill holes in P type. To produce enough energy this way we would need to cover an area akin to the size of Paraguay; the supply is unreliable;
rare earth metal mining would disturb ecosystems ;and there would be need of facilities to recycle them after 20 to 30 years but research and development would really help as indicated by the fact that since 1976, price of solar PV modules
has fallen by more than 90%
wind power
Wind power is the cheapest form of onshore energy and is set to get cheaper and more stable because each turbine is generating more energy in its life, turbines are spending more time at full capacity and because of increased
production, economies of scale are being enjoyed. We can increase rated power, the point at which more energy wonât be produced with faster wind, by increasing turbines diameter but they become expensive to transport and have
to be assembled on site and made of more stronger material so they donât break so easily which is also expensive; and capacity factor, the fraction of time the turbine is running at its rated power, by placing turbines at sea and higher up,
like one tech that flies kites to generate electricity. Problems: they take up a lot of space and disrupt landscapes but can be built on the sea and in between farms; they kill birds but can be stopped during migration, their height adjusted
and not be situated in areas with lots of rare birds; they make noise but can be made from different materials and have quieter motors; they disrupt radio waves but can be made from wave soaking materials.
hydropower
60% of modern renewable energy comes from hydroelectric power, which also accounts for 16% of our overall electric production. Water is trapped in a reservoir behind the dam and when we want to use its gravitational potential energy,
we open a small gate which lets it flow through a channel to spin a turbine. It emits less greenhouse gasses than burning fossil fuels, is renewable, has countless other uses, and, most importantly, allows us to store the energy
it produces. Although it has high initial costs and building it is expensive, since it requires no raw materials to run, the operating costs are low and they last longer. On the other hand, The USA could produce as much energy with 13%
of the space; they flood land and flooded plants die and release greenhouse gasses, and account for 1.3% of total emissions, as much as the whole of brazil, but this can be solved by building them steeper and on river systems
with lesser nutrients; reservoirs tend to rise and fall and plants onshore die repeatedly, further adding to methane emissions; they disturb migrations of fish upriver which can be solved with fish ladders; they release only the colder
water at the bottom with less oxygen. Tidal innovations are coming up but they are either too docile or damaging and it will remain versatile in developed and developing countries, increasingly so as solar and wind are promoted
and we look for a more reliable source
nuclear power
The energy sector would produce 90% less CO2 if we only used nuclear energy. Nuclear power is based on nuclear fission, utilising Einsteinâs E=mcÂČ, converting mass into energy by shooting a slow neutron which would split a
uranium 235 isotope with 92 protons and 143 neutrons, unlike a fast neutron that would just bounce off; this process yields two smaller atoms, a few neutrons and energy but it can get out of hand if not controlled and cause a chain reaction.
Fast moving neutrons are passed through A moderator like water to slow them down enough to cause just one split, the primary circuit absorbs the energy, it heats the secondary circuit of water it passes through, steam turns a turbine
and the water is cooled and reused. Nuclear power causes only 0.07 deaths per TWh, in comparison to the 24.6 deaths per TWh caused by coal, but the handful of accidents are noticeable; we end up with depleted uranium 238
that is not hazardous when kept out of the body and radioactive waste that is still harmful for humans and nature for thousands of years to come and we donât know what to do with; and it is grossly expensive and not even considered profitable in western countries.
generation IV nuclear
Multiple Small modular reactors parts can be transported to the site and assembled there to generate the same power as conventional big reactors, making them ready to install immediately when a state decides to implement them and
solving the problem of high initial costs, long construction period and nuclear explosions. Molten salt reactors use molten salt as coolant instead of water and can reach temperatures as high as 850°C as soon as a material is fabricated
than can contain such a hot substance, has 30% higher fuel efficiency and will switch off if it overheats. Spent fuel is more dangerous than depleted uranium 238 but travelling wave reactors could
produce 80% less radioactive waste( by mass) by in theory recycling it to make their own fuel,
by adding a neuton to uranium 238 to make it uranium 239 which quickly decays and becomes the radioactive plutonium 239 which will now power the nuclear fission reactions.
geothermal energy
The earthâs core formed when debris were pulled together by gravity, an energy releasing process whose heat remains to this day, and some of the debris were unstable radioactive material which give off energy to become stable even today,
thus extracting this heat has zero fuel costs, low running costs and low average net costs of electricity per unit but high start up costs of geothermal mapping tools, seismic testing and exploratory drills to see whether an area is suitable,
making it a risky investment . At the lowest temperature, the most constant and common use of geothermal is pumping fluid 5 meters below ground to exchange heat; warmer reservoirs can be used to pump hot water directly;
the hottest source used to generate electricity through steam-spinned turbines requires 150°C and thus not all sources can be used. While we have the technology to dig at scale, it is costly and difficult so to be able to generate electricity
the site needs to have heat close to the surface, water to carry heat from rocks to the surface and permeable rocks to allow water to flow through. Profitable dry steam power plants utilize underground sources of steam
but while start up costs are low, underground sources hot enough to generate electricity are rare; common flash steam systems spray high pressure, underground hot water into low pressure tanks to convert them into steam;
hot water indirectly heats a second liquid with low boiling temperatures in the binary system when it isnât hot enough to generate electricity and there are minerals in it that could damage the turbine; enhanced geothermal systems
inject fluid into the ground to fracture the hot rock and create an artificial reservoir.
Nuclear fusion
(Deuterium(1p1n)+tritium(1p2n))higher mass=(helium+1 neutron)lower mass+energy(lost mass).
Therefore, there are no CO2 emissions, just harmless helium; no nuclear waste; and no risks of meltdown. However, the positive nuclei repel each other and bringing them together requires more energy than is released.
The ratio of input to output power is often called âQâ.
