CHAPTER 4.1

• Data that reinforced the relationship between ice cores from Greenland and other paleodata showing sometimes catastrophic climate change over a short time, it was quite clear by 1990 that despite the natural changes to the planet's climate processes, the existing data had already accounted for it, and undoubtedly humanity's actions since the Industrial Revolution were increasing greenhouse gases and increasing global average temperatures
• The IPCC (Intergovernmental Panel on Climate Change) was founded in 1988 under the direction of the United Nations and World Meteorological Association at the request of its most senior members
• IPCC role


  To assess climate change data as it comes to light and to make proposals to the UN and its member bodies on what to do to face down the challenges of a warming world
• In the final decade of the millennium, climate science finally broke out of its niche within the Earth Sciences and began forming bonds elsewhere - anthropology, archaeology, geology, and even economics and business, as the changes required to mitigate our warming world would create a fundamental global economic shift
• Since the turn of the Millennium, few scientific issues have become so popular as a matter of public discourse as climate change
• The damage that science denial can do in any field is potentially limitless, but climate change is critical and a strong case in point because it is time sensitive
• The arrival of big data analytics has helped to further the collection, collation and analysis of data sets, making it far easier and faster than ever before to produce accurate results based on land temperature, sea temperature, and at various points in the atmosphere
• Big data analytics also allows scientists to process disparate data sets without intense labor
• One of the results of this is the understanding of the subtle nuances that exist between natural forcings (such as solar activity and volcanoes) and human-induced climate change such as greenhouse gas emissions
• Greenhouse gas


  A gas that absorbs and emits radiant energy within the thermal infrared range
• El Niño


  An oscillation in the temperature of the atmosphere and the ocean in the eastern equatorial Pacific, occurring roughly once every seven years
• La Niña


  The opposite effect of El Niño, occurring after a few months
• ENSO (El Niño-Southern Oscillation)


  1. Depletion and failure of replacement of the Pacific Trade Winds following the Pacific monsoon season

  2. Warm air creates an oscillation and the waters become warmer
• La Niña


  1. Trade winds are stronger than normal, moving warm water westward across the Pacific

  2. The east of the ocean is colder than normal while the west is warmer than average
• El Niño


  • Peruvian fishermen find that anchovy stocks are low
  • Precipitation shifts globally
  • Iberian Peninsula in Europe tends to be wetter from August to November
  • Tip of South America tends to have higher rainfall
  • Tropical Africa is drier than normal
  • Northern Europe tends to be much colder in the winter months
  • Central and western Europe will experience warmer than normal temperatures in the autumn
  • Eastern Seaboard in the US will experience lower precipitation between December and May
  • Eastern Seaboard in the US will experience colder temperatures between June and September
• La Niña


  • Central Mexico and the southern US can expect lower precipitation between the following December and March
  • Northern areas of South America will experience higher than average rainfall
  • Most of the central tropics from Africa through the Indian Ocean to the western Pacific will experience higher than average rainfall
• Madden-Julian Oscillation (MJO)


  Moves across a geographical area - eastwards along the tropics, bringing higher levels of cloud, increased precipitation and therefore the risk of rainfall
• Tropical weather events are predictable once MJO is on the move, this means preparing for extreme weather (potential drought and flooding) in the tropical areas
• MJO can have much longer range effects, creating knock-on effects as far away as the northern US, Canada, and northern Europe
• North Atlantic Oscillation (NAO)


  Describes fluctuations between the sea level atmospheric pressure from the areas known as the Azores High and the Icelandic Low
• Positive NAO


  • Warm westerly winds dominate the North Atlantic, bringing warm air from the southern US coastal states northeast towards northwestern Europe
  • British Isles tend to experience warm but wet weather
  • Colder weather in the northern coastal states and Canada on the Atlantic side and southwestern Europe
• Negative NAO


  • Southern US states experience cold and snowy weather conditions
  • Northern counterparts experience warmer weather
  • Scandinavia tends to be cold but dry
  • Mediterranean Basin is warmer and wetter
• North Pacific Oscillation


  Divided by northern and southern regions, with two phases - the Aleutian Below (south of the Aleutian Islands) and the Aleutian Above (north of the islands)
• North Pacific Oscillation "above" phase


  • North American continent is warmer except for certain areas of the western US with higher levels of precipitation over the Pacific Northwest
  • Impact on sea ice during the positive NPO with coverage being more extensive in Bering and Okhotsk Seas
• Pacific Decadal Oscillation (PDO)


  Occurs over much longer timeframes - measured in decades, typically lasting for around 20 or 30 years
• PDO


  • Impacts weather and climate, including frequency and intensity of hurricanes across the Pacific and even in the Atlantic
  • Land temperatures are increased while marine ecosystems' production of plankton reduces, impacting the wider ecosystem
  • When PDO and ENSO occur together, impacts are magnified but when they are out of phase, effects are effectively mitigated
• Interdecadal Pacific Oscillation (IPO)


  Similar to the PDO but it covers the area of the Pacific area south of the PDO (south of the 20 degrees N latitude), and lasts anything from 15 to 30 years
• Positive IPO


  Temperatures are lower in the Pacific tropical and subtropical areas but warmer farther to the north
• Climatology is primarily concerned today with the human impact on climate change and the various "forcings" that are already causing problems
• Greenhouse gases


  Methane, water vapor, nitrous oxide and carbon dioxide
• Water vapor


  Creates a feedback - precipitation and cloud cover increases, leading to higher temperatures, but also creates more rainfall which can cool surfaces but can lead to flooding in some areas
• Nitrous oxide


  A byproduct of agricultural processes
• Hurricanes are large swirling storms that form over warm ocean waters
• The sun is the main source of energy on Earth.
• Energy from the Sun reaches the surface as shortwave radiation, which can be absorbed by land or water surfaces.
• Shortwave radiation that hits clouds is reflected back into space.
• Energy from the Sun reaches the surface as shortwave radiation (SW).
• Shortwave radiation is absorbed by land or vegetation and then re-radiated as long wave radiation (LW) back into space.