Thanks  for  tuning  into  my  talk.  My  name  is  David  Meintrup.  I'm  P rofessor  at   Ingolstadt  University  of  Applied  Science.   Today  I'm  going  to  talk  about  the  Earth,  the  climate  and  you.

Let's  start  with  a  warm  up  talking  about  the  climate,  no  pun  intended.  Please  consider  these  four  actions.  Imagine  you  would  keep  doing  these  for  one  year.  No  plastic  bags,  go  vegan,  drive  fuel- efficiently,  or  always  switch  off  stand  by  modes.  Can  you  order  them  by  the  amount  that  they  reduce  your  carbon  dioxide  footprint?  No?  Well,  don't  worry,  you're  in  good  company.

A  study  that  was  performed  by   A.T. Kearney i n  2019  came  to  the  conclusion  that  we  generally  have  no  clue  what  reduces  our  personal  footprint.  They  gave  people  seven  personal  actions,  from  no  plastic  bags  to  one  flight  less  per  year  to  region and  season  food,  et cetera.   You  can  see  what  people  thought,  their  answers  on  the  left  side.  I  will  give  you  the  correct  answers  at  the  end  of  my  presentation,  but  I  can  already  tell  you  that  people  were  completely  wrong.

I  stumbled  across  this  study  a  year  ago,  and  I  will  openly  admit  I  had  no  idea  either.  But  how  are  we  going  to  save  our  planet  if  we  don't  know?   This  was  the  motivation  for  today's  presentation.

I'm  mathematician  by  education,  and  I've  been  promoting  statistical  literacy  for  many  years.  There's  this  famous  quote,  "Statistics  is  too  important  to  be  left  to  statistic ians  and  I  think  that  the  same  is  true  for  the  climate.  We  need  climate  literacy  to  know  and  understand  the  Earth's  climate,  impacts  of  climate  change,  and  approaches  to  adoption  and  mitigation.

In  the  same  spirit,  I  would  like  to  say  climate  change  is  too  important  to  leave  it  to  climatologists.  And  despite  the  fact  that  I'm  a  mathematician,  I  wanted  to  study  the  topic  and  talk  about  it.  In  one  sentence,  the  goal  of  my  presentation  today  is  to  increase  my  own  and  everybody  else's  climate  literacy.

I  would  like  to  do  this  by  answering  three  questions.  Why  exactly  does  climate  change  happen?  Since  when  do  we  know?  And  what  can  each  and  everybody  of  us  do  about  it?

Let's  start  with  another  question.  Did  the  average  global  temperature  increase?  Yes,  no,  or  one  can't  say?  Well,  as  you  all  know,  the  answer  is  obviously  yes,  and  that  is  not  difficult  to  prove  as  one  can  simply  measure  the  temperature.

H ere  you  see  the  development  of  the  global  temperature  over  the  last  140  years.  C ompared  to  the  reference  interval  from  1880 -1910,  we  have  an  increase  of  approximately  1.1  degrees  Celsius.  In  addition,  it  took  only  30  years  to  double  the  increase  from  0.5  degrees  to  one  degree.

Next  question,  what  causes  global  warming?  Well,  again,  I  guess  that  you  are  all  familiar  with  the  answer.  Carbon  dioxide  emissions  from  burning  fossil  fuels  like  coal,  oil,  and  gas.  But  do  you  also  remember  why?  Why  do  these  emissions  cause  global  warming?

Well,  the  answer  is  the  greenhouse  effect.  And  I  would  like  to  present  a  few  more  details  on  that.   The  temperature  on  Earth  is  completely  determined  by  the  radiation  balance.  We  have  incoming  solar  radiation  that  is  partially  absorbed  and  partially  reflected  by  the  Earth  and  the  atmosphere.   From  the  absorbed  energy,  one  part  is  radiated  back  into  space  as  heat,  and  another  part  is  absorbed  by  greenhouse  gasses  and  then  reemitted  down  to  the  Earth.  And  this  part  is  actually  what  is  called  the  greenhouse  effect,  and  that  is  causing  the  global  warming.

Now,  which  gas  contributes  most  to  the  greenhouse  effect?  Is  it  water  vapor,  carbon  dioxide,  methane,  or  ozone?  I  guess  that  most  of  you  will  have  answered  carbon  dioxide,  but  actually  it's  a  trick  question.  Because  the  trap  here  is  that  I  didn't  ask  about  the  manmade  greenhouse  effect.

Let's  have  a  look  at  the  details.  Greenhouse  gasses  actually  keep  us  warm.  Without  atmosphere  and  therefore  without  any  greenhouse  gasses,  the  temperature  on  Earth  would  be  on  average  minus  18  degrees.  No  life  on  Earth  would  be  possible.  Now,  if  we  add  an  atmosphere,  including  natural  greenhouse  gasses,  water  vapor,  methane,  and  carbon  dioxide,  approximately  at  a  level  of  280  parts  per  million,  then  we  have  a  natural  greenhouse  effect.   This  rises  the  temperature  from  minus  18  degrees  to  plus  50.  So  it's  a  huge  effect,  an  increase  of  33  degrees,  and  this  is  what  is  called  the  natural  greenhouse  effect.  And  the  main  gas  contributing  to  it  is  water  vapor.

Now,  if  we  continue  and  we  add  anthropogenic  manmade  greenhouse  gasses,  for  example,  we  raised  the  carbon  dioxide  to  410  parts  per  million,  which  is  more  or  less  where  we  are  right  now,  then  we  also  add  another  layer  of  warming,  as  I  said  before,  approximately  1.1  degrees,  and  this  leads  then  to  an  average  temperature  of  16.1.  And  in  this  additional  manmade  greenhouse  gas  effect,  indeed,  carbon  dioxide  is  the  most  important  contributor.

You  can  see  this  confirmed  on  this  slide.  R oughly  two  thirds  of  the  greenhouse  effect  is  caused  by  carbon  dioxide.  Methane  contributes  more  or  less  one  sixth.  There's  an  important  difference  between  these  two  gasses,  though,  and  this  refers  to  their  lifespan.  Every  molecule  of  carbon  dioxide  in  the  atmosphere  is  adding  to  global  warming  for  the  next  100  years  and  more.  Methane,  on  the  other  hand,  has  a  lifetime  of  about  nine  years.  So  cutting  methane  emissions  is  a  very  quick  and  good  fix  for  short  time  period.  But  on  the  long  run,  we  will  have  to  reduce  carbon  dioxide  emissions.

Let's  have  another  look  at  the  greenhouse  effect.  The  first  slide  I  showed  you  was,  of  course,  an  oversimplified   as  this  is  tool,  but  it  has  some  more  details  on  it.  I  would  just  like  to  repeat  two  elements.  On  the  right  side,  you  have  the  greenhouse   this  very  important  down  welding  radiation.  And  on  the  left  side,  you  have  the  information  that  part  of  the  incoming  radiation  is  reflected  by  the  Earth's  surface.  And  of  course,  the  brighter  the  surface  is,  the  more  radiation  is  reflected.  This  is  important  to  understand  some  feedback  loops.

The  feedbacks  are  self  reinforcing.  For  example,  the  most  famous  one  is  the  ice- albedo  feedback.  The  surface  of  the  ice  reflects  85 %  of  the  solar  energy,  only  15 %  is  absorbed.  The  dark  sea,  however,  only  reflects  7 %  of  the  energy  and  absorbs  93 %.  Now,  if  global  warming  induces  that  the  ice  is  melting  and  turning  into  dark  sea,  then  more  energy  is  absorbed,  causing  more  global  warming,  causing  more  ice  to  melt,  et cetera.

The  same  feedback  happens  with  the  melting  of  the  permafrost  that  is  a  huge  storage  for  methane  and  carbon  dioxide.   We  can  even  see  an  increase  over  time  of  water  vapor  that  also  obviously  has  a  feedback  loop  because  warmer  air  can  store  more  vapor.

Unfortunately,  these  effects  are  difficult  to  quantify.   In  fact,  they  are  not  included  in  many  models.  Let's  quickly  summarize  the  physics  that  we've  seen  so  far.  Temperature  on  Earth  is  a  question  of  radiation  balance.  The  natural  greenhouse  effect  is at  about  33  degrees  and  is  a  prerequisite  for  life  on  Earth.  The  anthropogenic  manmade  greenhouse  effect  consists  in  adding  additional  greenhouse  gasses  in  particular,  carbon  dioxide  and  methane.  Carbon  dioxide  in  the  atmosphere  increased  from  more  or  less  280  part  per  million  to  410,  inducing  an  increase  in  global  temperature  of  1.1  degrees  Celsius.

If  we  want  to  stop  the  global  warming,  this  results  in  stopping  greenhouse  gas  emissions.   Let  me  turn  to  the  second  question.  Since  when  do  we  know?  Longer  than  you  think.  Many  of  you  might  be  familiar  with  the  Mathematician  and  Physicist, Jean-Baptiste Joseph Fourie  Jean  Bartiste  Joseph  Foyer.  He  was  the  first  one  to  realize  that  the  temperature  on  Earth  is  much  higher  than  one  would  expect.   The  explanation  he  came  up  with  was  that  the  atmosphere  acts  as  an  insulator,  storing  heat  that  would  otherwise  escape.

Roughly  30  years  later,   John Tyndall proved  that  Fourier  was  actually  right.  He  demonstrated  that  carbon  dioxide  absorbs  and  emits  infrared  radiation.  Finally,  at  the  end  of  the  century,  the  Swedish  Chemist,  Svante Arrhenius,,  was  able  to  quantify  the  greenhouse  effect,  the  amount  of  global  warming  due  to  the  carbon  dioxide  emissions.

By  the  way,  living  in  Sweden,  he  considered  this  a  positive  effect.  He  hoped  that  life  would  become  more  pleasant  with  a  little  bit  warmer  temperatures.  I  would  like  to  jump  to  the  '70s  and  show  you  30  seconds  from  a  very  popular  German  TV  show  at  that  time.  The  host  describes  in  detail  how  global  warming  works.  It's  in  German,  unfortunately,  but  I  put  subtitles  in  English  so  that  you  can  read  it.  A gain,  this  is  from  1978.

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The consequences  will be  dramatic.  Isn't  it  incredible  how  precisely  they  predicted  global  warming  in  1978?  I  find  this  amazing  every  time  I  see  it.   This  TV  host  was  not  the  only  one  who  knew.  Many  companies  knew,  including.

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Here  is,  since  then,  Exxon.  Exxon  knew,  and  Exxon  knew  exactly.  You  might  have  heard  about  it  because  it  just  recently  made  the  news.  A  group  of  scientists  just  published  a  science  article  assessing  Exxon Global  warming  projections.

I  would  like  to  read  two  sentences  from  the  abstract.  The  first  one  is,  "Their  projections  were  also  consistent  with  and  at  least  as  skillful  as  those  of  independent  academic  and  government  models."  In  other  words,  they  had  excellent  predictions  and  scientists.   The  final  sentence  says,  "On  each  of  these  points,  however,  the  company's  public  statements  about  climate  science  contradicted  its  own  scientific  data."  This  is  a  very  polite  way  to  express  that  they  invested  a  huge  amount  of  money  to  actually  dismiss  global  warming.

As  we  do  have  the  documents,  I  can  show  you  this  in  a  little  bit  more  detail.   This  is  the  original  letter  from  Exxon  from  1982  called  CO₂  Greenhouse  Effects,  and  ending  with  the  remark  "Not  to  be  distributed  externally.  For  internal  use  only."

Exxon  estimated  the  development  of  carbon  dioxide  in  the  atmosphere  and  global  temperature  until  2100.  So  let's  zoom  in.  Here,  we  see  the  year  2022.  And  the  corresponding  most  probable  measurements  that  Exxon  predicted  were  420  carbon  dioxide  and  increase  of  temperature  of  1.1  degrees.  This  is  spot  on,  right?  A ll  one  can  say  is  excellent  work.

By  the  way,  if  you  wonder  why  they  were  interested  in  this  question,  it  was  partially  because  they  knew  that  global  warming  would  lead  to  a  rise  of  sea  level  so  that  they  had  to  build  their  oil  platforms  higher.  Now,  with  the   First World Climate Conference  in  1979,  did  climate  policy  have  measurable  success  over  the  last  40  years?  This  is  my  final  question  to  wrap  up  the  historic  part  of  this  talk.  Yes,  no,  or  one  can't  say?

Very  unfortunately,  the  answer  is  a  very  clear  no.  Below  the  graph,  you  see  the  famous  temperature  stripes  showing  the  increase  of  temperature  over  the  last  60  years.  The  graph  itself  shows  the  carbon  dioxide  in  the  atmosphere.

W e  have  the  First  World  Climate  Conference,  the  First  IPCC  Report,  the  First  UN  Climate  Conference,  the  Kyoto- Protocol,  the  Copenhagen  Accord,  and  finally,  the  Paris  Agreement.   During  all  these  meetings,  conference,  and  agreements,  carbon  dioxide  in  the  atmosphere  increased  from  316- 420,  the  measure  that  we  have  right  now.   None  of  these conference,  agreement  or  meetings  had  any  measurable  effect  on  our  actual  situation  regarding  climate  change.

Finally,  not  to  leave  it  to  these  a  little  bit  depressing  news,  what  can  each  and  every  one  do  about  it?  Let  me  first  very  quickly  remind  you  that  there  is  a  practically  linear  relationship  between  temperature  increase  and  global  emissions.   If  we  want  to  keep  the  1.5  degrees  goal  from  the  Paris  Agreement,  we  can  very  easily  estimate  that  we  have  left  approximately  500  gigatons  of  carbon  dioxide.  This  was  in  2020,  three  years  ago.

Three  years  ago,  we  had  500  gigatons  left  for  the  1.5  degree  goal  of  the  Paris  Agreement.  Now,  if  we  relax  this  a  little  bit  to  two  degrees,  then  we  have  1,350  gigatons  left.  To  demonstrate  the  current  status  of  our  emissions,  I'm  going  to  switch  to  JMP.

Let's  start  with  having  a  look  at  the  global  emissions.  If  we  look  at  it  historically,  since  1850,  you  can  see  the  map  on  the  left  side  of  the  main  emitters,  and  I  have  the  data  here  on  the  right  side,  the  three  top  units  that  contributed  historically  to  global  emissions  are  the  United  States,  responsible  for  one  quarter,  a  little  bit  less  the  European  Union,  and  13 %  from  China.   This  adds  up  to  roughly  60 %  that  these  three  top  units  are  responsible  for  historically  since  1850.

Now,  if  we  look  at  the  current  status,  so  this  is  data  from  2018,  you  can  see  here  that  the  top  three  are  still  the  same,  but  the  order  changed.   China  is  now  by  far  the  country  emitting  most,  followed  by  the  United  States,  and  third  in  place  is  the  European  Union.  T hese  three  still  add  up  to  roughly  50 %  of  global  emissions  per  year.  The  conclusion  here  is  that  without  these  players,  we  are  not  going  to  get  anywhere.

Now,  to  make  the  comparison  a  little  bit  fairer,  let's  look  at  emissions  per  person.   Here  in  the in  this  lower  graph,  you  see  the  emissions  per  capita  for  different  countries.  The  top  ones  are  the  Gulf  states  like  Qatar  and  similar  countries,  followed  by  a  second  group  of  high  emitters,  Australia,  Canada,  and  the  United  States.   Then  there  is  a  third  group  that  consists  of  China  and  the  European  countries  in  the  middle.   Then  we  have  low- emitting  countries  typically  found  in  Africa.

Now,  please  follow  me  on  the  following  calculation.  I  said  before  that  in  2020,  we  had  500  gigatons  left.  Now,  it's  easy  to  turn  this  into  a  per- person  budget,  which  is  56  tons. I f  we  want  to  be  carbon  neutral  by  2050,  this  leaves  us  28  years,  56  tons.  T he  personal  budget  on  average  per  year  that  is  compatible  with  the  1.5  degree  of  Paris  is  two  tons  per  person.  This  is  this  red  line  that  you  see  down  here.

Now,  let's  look  at  the  United  States,  for  example.  For  the  last  three  years,  the  United  States  have  emitted  approximately  18.4  tons  per  person.   In  three  years,  they  already  used  the  56  tons  that  they  had  left  until  2050.  On  the  top,  you  see  the  years  left  until  the  corresponding  country  has  entirely  used  its  budget.  And  you  can  see  that  the  US,  Canada,  Australia,  and  Qatar,  they  are  at  zero  or  below.  In  other  words,  these  countries  already  have  used  everything  they  had  left  to  keep  the  Paris  goal  of  1.5 %.  Every  breath  they  take  now,  every  car  they  drive,  every  plane  they  fly,  is  already  on  the  depth  side  towards  this  climate  goal.  D on't  worry,  the  Europeans  are  all  going  to  follow  in  a  future in  a  couple  of  years.

The  conclusion  of  this  is  unfortunately  that  we  have  absolutely  no  chance  to  reach  the  1.5  climate  goal  of  the  Paris  Agreement.  Every  ton  that  we  can  save  is  good,  but  the  1.5  degree  goal  is  gone.  Unfortunately,  there's  agreement  on  this.

If  we  now  look  at  the  global  emissions  by  sector  to  a  little  bit  approach  the  question  in  what  area  we  can  personally  contribute,  then  you  can  see  that  almost  three  quarter  of  the  emissions  come  from  burning  fossil  fuels,  oil,  gas,  and  coal.  So  if  someone  says  the  climate  crisis  is  a  global  energy  crisis,  he  or  she  is  absolutely  right.  Almost  three  quarter  of  the  emissions  are  due  to  burning  fossil  fuels.  20 %  come  from  agriculture  and  then  they  are  cemented  waste.

Here  in  the  middle,  you  see  this  in  a  little  bit  more  detail,  and  I  would  just  like  to  emphasize  one,  and  this  is  livestock.  Livestock  is  responsible  for  8 %  of  global  emissions.  What  that  means  is  the  following.  If  you  put  all  the  cows,  pigs,  and  sheep,  and  everything  in  one  country,  looking  at  their  emissions,  they  would  be  number  three  in  the  world.  There's  China,  the  US,  and  all  the  animals.  The  country  consisting  of  all  the  animals  would  be  the  third  biggest  emitter  on  this  planet.

This  is  one  reason  why  agriculture  is  a  huge  contributor  and  is  actually  the  field  with  the  highest  impact  for  your  personal  influence.  Followed  by  buildings,  meaning  how  you  heat  and  the  electricity,  and  the  third  question  is  how  you  move.  So  transportation,  buildings,  and  agriculture  are  the  three  big  contributors  where  you  have  personal  influence  on  global  emissions.

I  would  like  now  to  turn  the  attention  to  these  three  fields.  I  will  start  with  transportation  because  I  think  this  is  the  best  known.  But  it's  always  good  to  look  at  this  personal  budget.   Let  me  remind  you,  your  personal  budget  is  two  tons.  One   transatlantic  flight  Frankfurt- New  York,  consumes  four  tons.   Twice  your  personal  budget  is  spent  on  one   transatlantic  flight.

There  are  other  ways  to  use  your  personal  budget  quickly.  One  luxury  cruise  seven  days,  2.8  tons.  Driving  your  fossil  fueled  car  for  one  year,  2.3  tons.  Everything  already  above  your  personal  budget and  you  haven't  eaten  anything  yet.

Generally,  it  will  be  known  to  you  that  taking  a  plane  is  the  worst  way  of  moving.  You  cut  emissions  more  or  less  by  half  if  you  take  the  car  and  you  cut  emissions  by one  tenth  if  you  take  the  train.   Of  course,  public  transportation  is  better  than  private  one,  and  the  best  way  to  move  is  if  you  use  your  own  muscle  on  a  bicycle  or  just  by  walking.

Now,  for  buildings,  the  situation  is  quite  clear.  60 %  of  the  emissions  come  from  direct  or  indirect  use  of  fossil  fuels  by  heating,  cooking,  and  electricity.  T he  conclusion  here  is  very  easy.  Turn  to  renewable  sources  for  your  power  use  in  your  house.  Heating,  cooling,  electricity.  Turn  this  into  a  greenhouse  and  you  will  significantly  contribute  to  a  reduction  of  your  carbon  footprint.

20 %  almost  of  the  emissions  in  the  building's  area  come  from  building  material.  And  it's  very  interesting  that  there's  a  lot  of  research  going  on  to  replace  classic  building  material  by  carbon  dioxide  neutral  or  even  negative  one.  And  I  included  one  example,  this  is  a  company  from  Switzerland  that  actually  stores  carbon  dioxide  into  recycled  concrete  and  tries  to  reduce  the  carbon  footprint  by  this.

Finally,  agriculture.  I  have  here  the  data  for  four  different  diets  and  their  carbon  footprint.  It's  data  from  the  US.  It's  not  that  easy  to  find  the  data  for  other  countries,  this  is  why  I  took  the  one  from  the  US.

The  average  American  diet,  again,  uses  your  full  budget  of  two  tons.  If  you  leave  out  dairy  or  if  you  leave  out  meat,  so  you  turn  to  vegetarian,  this  significantly  reduces  your  footprint.  But  the  really  huge  step  is  leaving  out  both  and  becoming  a  vegan.  If  you  wonder  why  this  is  the  case,  it's  because  of  the  footprints  of  different  types  of  food.  You  can  see  that  all  the  vegan  food  here  is  in  the  lower  section.  This  is  split  in  methane  and  non- methane  greenhouse  gasses.  And  all  the  high  emitters  are  in  the  upper  ones.  A ctually,  I  didn't  arrange  the  scale  right.

If  you  look  at  the  top,  beef  from  beef  herds,  it's  not  40,  neither  50  nor  60,  nor  70.  It's  actually  100  kilograms  per  kilogram  of  the  corresponding  food.  I f  you  only  want  to  do  one  thing,  in  your  diet,  leave  out  beef.  Personally,  I  find  one  of  the  most  impressive  statistics,  this  one,  29 %  of  our  Earth's  surface  is  land,  71 %  is  habitable.  Half  of  it  we  use  for  agriculture.  Of  this  part,  77 %  is  directly  or  indirectly  used  for  livestock.  This  is  one  third  of  the  habitable  land,  but  we  only  produce  18 %  of  calories  from  meat  and  dairy.

This  is  why  the  lead  author  of  the  corresponding  article,  Joseph  Poore  says,  "A  vegan  diet  is  probably  the  single  biggest  way  to  reduce  your  impact  on  planet  Earth,  not  just  greenhouse  gasses,  but  global  acidification,  eutrophication,  land  use,  and  water  use."  He  himself  turned  vegan  after  conducting  the  study.

Let  me  just  wrap  up  a  little. H ere  are  the  four  actions  I  introduced  in  the  beginning,  and  I  hope  that  by  now  it  will  be  no  surprise  anymore  to  anyone  that  going  vegan  is  the  most  efficient  thing  you  can  do.  No  plastic  bags  is  good  for  the  environment,  but  it  doesn't  really  have  an  important  impact  on  the  carbon  footprint.

Here  are  the  answers  from  the  survey  I  showed  you.  And  as  you  can  see,  no  plastic  bags  was  the  answer  with  the  highest  rank,  highly  overestimated,  just  like  only  eating  regional  and  seasonal  food.  And  on  the  other  hand,  reducing  meat  was  highly  underrated.

I  would  like  to  wrap  up  with  a  quote  from  Al  Gore,  where  maybe  because  it's  not  100 %  clear  that  he  said  it,  "Vote,  voice  and  choice."  What  can  you  do  personally?  You  can  vote  in  every  election,  make  climate  policy  a  priority,  and  let  officials  know  what  you  want.  Make  your  voice  heard.  Support  organisations,  talk  about  it  in  your  company,  et cetera.

Finally,  your  personal  choices  matter.  Ideally,  eat  a  plant- based  diet,  reduce  use  of  fossil  fuels  for  mobility,  in  particular  flying,  and  make  your  home  green  by  using  renewable  energy  for  electricity  and  heating.

My  contribution  to  making  our  voices  heard  was  to  give  this  talk  today.   I  would  like  to  thank  you  very  much  for  taking  the  time  to  listen  to  my  message.