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science

an activity that aims to further our understanding of why things happen as they do in the natural world

self-correcting

through testing and refining our knowledge n understanding

scientific method

used to probe and discover new things about nature, relying on our explanation and testing these explanations. if explanations are not falsified = explanation confirmed

roles of scientific observations

1. identify and focus on relevant facts
2. provide clues to possible explanations
3. provide evidence + testing the evidence


1. tricky to narrow relevant data
2. difficult to gather necessary data

concerns to address when making scientific observations

1. do we have a clear sense of the relevant phenomena?
2. did we ensure we didnt overlook anything in the observation process?
3. based on facts or conjecture (opinions from incomplete info) + assumptions?
4. any biases?


1. any comparative info?

scientific revolution

too many anomalies → scientists become critical of current understanding → new ideas → scientific revolution

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definition: scientific community accepts new theories, concepts and methods brought about by anomaly and abandons the old ideas

understanding of the natural world based on authority

accepted idea, cannot be challenged/argued - heresy! → people did not challenge norms

evidence-based understanding of the natural world

use of scientific method to explain phenomena, put aside past beliefs and biases to observe and test explanations.

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use of rigorous testing and observations and instruments

importance of scientific community

peer-review + cross checked to reduce individuals being blinded by own expectations, beliefs and biases

industrial revolution

great technological innovations changed the world from relying on muscle power to relying on efficient and effective machines

good contributions of steam engine

E:


1. increased pdct of goods
2. facilitated mining of coal (pumped out water to make deeper mines more accessible)
3. improved efficiency of transportation of goods via trains/ships

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S:


1. employment oppostunities → increased income and SOL
2. improved agriculture yield → reduced famile
3. drop in mortality rate (food more accerssible + better sanitation)

bad contributions of steam engine

P:


1. increased pollution due to burning of fossil fuels

S:


1. spread of diseases due to lack of knowledge of germs n hygiene

impact of steam engine on pop growth in industrialized nations

1. drop in mortality rate → rapid rise in world pop

other implications of steam enginee

P:


1. climate crisis (global warming) → increasing pop but still reliant on fossil fuel for energy
2. loss in biodiversity + possible extinction

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3 things to do before BDTK (baloney detection toolkit)

1. possess a skeptical mindset
2. be aware of ur own biases (confirmation, availability, illusory truth bias)
3. guard your buttons (triggering certain emotions)

confirmation bias

seek info that alr supports smt u believe in + dismissing info we disagree w

availability bias

use info we can most readily recall (mental shortcut)

illusory truth bias

tendency to believe false info after repeated exposure

tools in bdtk

1. how reliable is source of claim (author, organization) → conduct lateral reading
2. source’s perspective (purpose of info, is it funded by any org)
3. positive evidence? (directly supports claim, relevant, reliable and not misrepresented) → lateral reading, reverse search photos


1. not scientific evidence: testimonials, eyewitness accounts, statements
2. evidence that shoots down other alts isn’t evidence that the current explanation is correct
4. where does most of the other evidence point? → lateral reading
5. have the claims been verified by someone else?
6. flawed reasoning?

scientific explanation

account of how or why something is the case, needs to be testable/subj to falsification for it to be scientific

hypothesis

tentative/unproven, a hunch that is not subj to testing/falsification yet

theories

conceptual framework for providing explanations, general structures that are capable of explaining a wider variety of phenomena than a hypothesis

contains well-tested, well-confirmed rules and processes that reveal underlying explanations

3 types: well-established, obsolete/superseded, newly proposed

well-established theories

heavily tested repeatedly, provides depth and breath of explanatory power

obsolete/superseded

previously thought to be correct, now replaced bc new evidence proved it wrong

newly proposed

can also be used to explain both phenomena and anomalies. still undergoing investigation and testing

correlation

2 properties/traits/charact are linked

3 types: perfect (1-1), positive, negative

j bc smt is correlated doesnt mean they have a causal rship

causation (cause n effect)

cause precedes effect

combination of causes can lead to single effect

same effect can result from diff causes

can involve a series of linked causes and effect:

* proximate causes (directly related, a→ b)
* remote causes (indirectly related, a → b → c)

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underlying process

fundamental processes, description is reduced to a basic lvl (reductionist approach)

laws

scientific law, usually universal

function

explain smt based on the purpose it fulfils

can be used to explain human behavior

occam’s razor

choose the least complex explanation → most plausible!

more complexities = greter chance smt is wrong

but simplest explanation =/= correct! need to test it (scientific method)

scientific model

cut-down, simplified representation of real-world objects

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explain phenomena AND can be used to test explanations, make predictions, projections and enhance our understanding, and for research

can end up producing wrong results as models are simplified, leaving too much of the real world out

BUT science is self-correcting → model can be improved

3 types of models: physical, conceptual, mathematical/computer

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constructed from concepts and principles to provide explanations for concrete applications

output tells us what should happen if explanation is correct

physical models

phy objects representing some aspect of nature

can be augmented w measurements

can be larger than actual thing (eg chemical models, dna)

conceptual models

cut-down version of reality w only the parts of interest included

can refer to diagrams n figures representing concepts n ideas -- only include the impt ones

can be abstract

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mathematical/computer models

math coded in computers to do tedious calculations

correlation: mathematically modelling rship bw 2 properties

laws: expressed using mathematical formula which can be used to derive even more expressions → when taken tgt, the equations represent how nature behaves

modelling scientist needs to consider all the necessary laws relevant to the queation → will involve a lot of data and equations

predictions vs projections

projections use “what if” scenarios

theories vs models

models: created from concepts and principles provided in a theory/hypothesis. used to test hypothesis, are concrete applications of a theory

experimental design

devise a set of circumstances in which th epredicted outcome should occur

flawed experiments can lead to

false rejection or confirmation

need to prove that alt explanation for result cant be the case

scientific community’s importance - if you dont think through experiment design carefully, someone else will

how is contemporary scientific research conducted

1. observations/questions
2. research topic area online (gather secondary data)
3. hypothesis (come up w a testable explanation - can be new or existing, or your own)
4. test w experiment (expensiv so needs funding - proposal needs to be prepared, submitted, and reviewed)
5. analyse data


1. report analysis

precision

tightness of grouping, how close tgt diff measurements are to each other (statistical variability)

high precision = less randomness = low uncertainty

used to talk about instruments of diff precision

accuracy

how close all measurements are from the true value

systemic error: measured value differs from true value bc of accuracy

random errors: precision and uncertainty

trueness = how close the measurements are to the true value

randomized controlled double-blind trial

people selected at random to go either experimental/control

law of chance states that w enough subjects, both groups will resemble each other as closely as possible. the larger the groups size the better the cancellation of differences

blinding is placed on both subjects and experimenters → eliminate possibility of suggestibility influencing outcome

double blinding eliminates additional bias from pre-conceived beliefs to creep into outcome of the experiment (achieved through placebo effect)

margin of error

provides a range of possible values for results of experiment, rather than just one value

requires a confidence level to determine margin of error

larger sample size → lower margin of error → lower confidence interval → lower confidence level

confidence level

tells u how confident u are that the experiment you did contains the true value in the range given by the margin of error

lower margin of error → lower confidence interval and confidence lvl

statistically significant

determined by looking if there is any overlap in the confidence interval at high confidence lvl (95%)

if high overlap: q possible that difference is due to luck → inconclusive

effect size

larger sample size → reduces margin of error

3 rules of thumb to decide if study has established a statistically significant diff bw experimental and control group

1. no overlap in confidence intervals → diff is statistically significant at the 95%
2. overlap is

atmospheric composition

78% nitrogen

21% oxygen

1% argon

trace amts of: carbon dioxide, 4% water vapor…

joseph black

experimented w heating magnesium carbonate and collecting the co2 given off

reverent stephen hales (1671-1769)

first person to suggest that atmosphere may play a role in the growth of plants

empedocles of ancient greece

first to argue that all matter was composedf of the classical elements of water, earth, air and fire

jean-baptiste joseph fourier

first person to establish that the atmosphere plays a role in controlling the climate

nils gustaf ekholm (1900)

first time the term “greenhouse effect” appeared was in his work

theory of phlogiston

johann joachim becher and georg ernest stahl

phlogiston theory stated that all combustible materials were made of 2 parts


1. phlogiston - given off when substance containing it was burnt


1. dephlogisticated part - substance’s true form / calx

discovery of oxygen

1. 1604 michael sendivogius - recognised that oxygen is the same as the fas released when saltpetre is heated
2. 1621 cornelius jacobszoon drebbel - his ‘liquour’, presumably oxygen, could sustain up to 12 men in a submarine for 1-3h
3. 1771-1772 carl wilhelm scheele - produced oxygen by heating mercury oxide n various nitrates in experiments
4. 1774 joseph priestley - focused sunlight on mercury oxide in a class tube → released ‘dephlogisticated air’ bc it supported combustion n was totally consumed
5. 1774 antoine-laurent lavoisier (father of modern chemistry)


1. stated that combustion is alw n only to do w oxygen, which combines w other substances during combustion
2. established Law of Conservation of Mass upon which all modern chemistry is founded

john tyndall (1820-1893)

commonly credited w explaining the greenhouse effect

importance of water vapor and its impact on the atmosphere

co2 is 90x more effective @ absorbing infra-red radiation than air

methane is 403x

water vapor is 16000x

eunice foote

woman scientist, identified co2 as a ghg a few years before tyndall, but was marginalised (women are invisible in history of science)

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callendar effect

global temp increase is due to rising CO2 concentrations

keeling curve

shows co2 lvls are rising steadily, and also shows seasonal variation in co2

harmful effects of fossil fuel emissions

co2 is a strong absorber and back radiator of infrared radiations

greenhouse effect

the process that causes the surface to be warmer than it would have been in the absence of an atmosphere

global warming

an expected increase in the magnitude of the greenhouse effect, whereby the surface of the earth will be inevitably hotter than it is now

metaphor for greenhouse effect

atmosphere acts like a blanket, but volcanoes can break the blanked

black body

an object that absprbs all radiation and assuming the object is in thermal equilibrium

earth’s albedo

A=0.3

wien’s law

wavelength of peak of the spectral distribution in the single-layer atmosphere model, is inversely proportional to its temperature

history of establishing the scientific consensus on climate change

1. first mathematical model to predict effect of global temp of increasing co2: by svante arrhenius, joseph fourier, john tyndall and eunice foote
2. guy callendar: first to suggest the increase in co2 through burning of fossil fuels had led to an observed increase in earth’s surface temp
3. skepticism: water vapor > co2 (questioning the effect of co2 since both are ghg)


1. increase in co2 will significantly increase absorption of infra-red radiation → affect earth’s surface temps. hence, water vapor will not overwhelm the absorption due to co2

what is the ipcc

intergovernmental panel on climate change

an intergovernmental body of the UN mandated to provide objective scientific info relevant to understanding human-induced climate change, its natural, political and economic impacts and risks and possible response options

ipcc first assessment 1990

air temp increased by 0.3’C to 0.6’C over the last 100 years

ipcc second assessment 1995

global warming continues, most likely due to human activity

ipcc third assessment 2001

global warming likely due to an increase in ghg concentrations

gallup environmental poll

a measure of US’s public perception of the scientific consensus around climate change

there is a disconnection bw public perception of the lvl of consensus present among scientists studying climate change and the consensus among scientists themselves

weather

combination of temp, humidity, ppt, cloudiness, visibility and wind, at a particular place in the short term

short-term conditions of the atmosphere

climate

typical weather in an entire region for a very long time

climate change

a shift in those average conditions due to global warming (cause) → climate change (effect)

who keeps records on global temperature?

1. NASA (national aeronautics and space administration)
2. NOAA (national oceanic and atmospheric administration)
3. UK Met Office
4. JMA (japan meteorological agency)


1. Berkeley Earth

longest-running temp record

central england temperature25 data series (starts from 1659)

differences in datasets of temp records

1. big gaps over the oceans
2. polar regions and parts of africa and south america
3. issues of diff coverage, missing data, changes in instrumentation, mvmt of stations, human/technical error

proxy methods

definition: a variable which correlates w the variable of interest is measured, and then used to infer the value of the variable of interest

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used when variable cannot be measured directly

proxy data in reconstructing past temp

1. dendrochronology
2. coral reefs
3. ice cores


1. vostok station ice-core temp record

dendrochronology

widths of tree rings (wider = conditions favour growth)

coral reefs

bands of coral’s shell changes in thickness in temp, water clarity, or nutrient availability

ice cores

measures fraction of oxygen-18 in water, correlated w temp (higher oxygen-18 = colder climates)

vostok station ice-core temp record

core enables temp to be reconstructed for the past 420,000 years

since then, earth is in interglacial period (hotter) called the Holocene

rise in ghg

1. co2 variationsL from 180ppmv in glacial periods → 280ppmv in interglacial periods (pre-industrial revolution). since industrial revolution, rate of increase in co2 are unprecedented
2. methane concentrations increased from 600ppbv to over 1800ppbv (3x)


1. nitrous oxide increased from 270ppbv to 338ppbv

global carbon cycle

mvmt of carbon bw the carbon reservoirs in the earth system

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carbon reservoir = where chemicals reside

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burning fossil fuels increases carbon in atmosphere → increase in atmospheric carbon reservoir

suess effect

burning fossil fuels would dilute the amt of carbon-14 present in the atmosphere

human disruption to carbon-14 amounts in the atmosphere through:

testing of nuclear weapons — cited to mark the transition from the holocene to anthropocene (humans have become a dominant force of global env change)

understanding of phenomenon P

construct a model of P on the basis of a theory T

CMIP6

Coupled Model Intercomparison Project

consists of simulations from around 100 distinct climate models produced across 49 diff modeling groups

these models simulate the physics, chemistry and biology of the atmosphere, land and oceans in great detail

require some of the largest supercomputers in the world to generate their climate projections

President George H.W. Bush (the art of doubt)

**spoke of the need to take concrete action to protect the environment**

john sununu (bush chief of staff) (the art of doubt)

Bush Chief of Staff, John Sununu described Hansen’s work as “technical poppycock.” The science underlying the link between global warming and the combustion of fossil fuels, Sununu believed, was insufficient to warrant government action or societal expense.

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Oreskes and Conway

quick to identify the role of a non -profit conservative think tank, the George

C. Marshall Institute.

george c marshall institute

established in 1984 with a focus on science and public policy.

Robert Jastrow, William Nierenberg, Frederick Seitz.



Having worked together on an advisory panel to the Reagan administration on the Strategic Defense

Initiative, colloquially referred to as the Star Wars initiative, they decided to create the Marshall Institute to continue this work to defend the Strategic Defense Initiative in the face of what they believed was Soviet strength and U.S. weakness.

**-**

The opposition saw the Star Wars initiative as politically destabilizing because it implied a winnable nuclear war.

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Government intervention as the antithesis of the free market is the defining feature of the political

school of thought that is neoliberalism. Modern neoliberalism focusses on deregulation and releasing

the magic of the free market. For the Marshall Institute, a return to the regulation required to combat

environmental concerns, like climate change, was an anathema to their neoliberal political ideology.

second hand smoke - a national concern

n the 1950s,

the tobacco industry had launched a strategy that refuted and ridiculed the science that linked smoking

to health issues, including lung cancer.

**-**

Seitz and the Marshall Institute were joined in their battle against regulating second -hand smoke

seitz n marshall institute promoted doubt

. They argued that chlorofluorocarbons were not responsible for ozone loss in the stratosphere.

2\. They argued that the sulphur dioxide being released by coal -fired power plants was not responsible

for the acid rain that was destroying forests.

3\. For climate change, they argued that global warming was caused by natural variations in solar radiation; that any warming caused by greenhouse emissions is swamped by natural climate variations.

luntz memo

**-**

The approach outlined in the leaked Luntz memo encapsulates the history and continuing approach of

those peddling the contrarian position both inside and outside of politics. A significant f raction of the

public accepts the deniers’ allegations as true, or at least are confused by them, and therefore do not

know what to think or whom to trust. Science has been effectively undermined, which has eroded public

support for the decisive action needed to avoid the worst effects of global warming.

single cause fallacy

It assumes that because the climate has changed from natural causes before, it

can only be changing from natural causes now. This is committing what is known as the *single cause*

*fallacy*49. As the name suggests, this is when a phenomenon is falsely attributed to a single cause,

even though other causes are possible. It would be similar to saying that smoking cannot cause cancer

because people were getting cancer before cigarettes were invented.