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Overview: The Climate Change

Climate change is becoming more evident nowadays, in fact, recent bad weather conditions such as typhoons, hurricanes, devastating floods, and deadly heatwaves have ignited the interest of people in understanding the role of global warming in urging extreme weather conditions. These weather events are now considered as a big new pattern of more extreme weather all over the world, which is also caused by human-induced climate change. With this, people all over the world have to face the consequences and even the reality of climate change which happens in many parts of the world manifesting as increased volatility of extreme weather events.

Because of global warming, various types of extreme weather events increased and are now becoming more drastic and frequent and might continue to happen in the next decades if no actions are made. Intense precipitation, increases in extreme heat, drought, flash floods, these are all happening in different regions of the world. Heatwaves are becoming hotter and longer these days, heavy rains and flooding are becoming more frequent. 

That’s why technology is used to discover methods and tools to easily calculate climate changes. It was stated that the climate index is strongly correlated with global surface temperature, which has significantly increased as projected by climate models during the 1980s.

What is Climate Index?

A climate index is a simple diagnostic system that is used to characterize and quantify certain aspects of a geophysical system such as a circulation pattern.Various methods are applied to derive assorted indices.

The climate index also considers the risk factors due to climate change in various parts of the world that are affected by weather-related loss including storms, floods, heat waves, and others. 

There is also a Climate Change Performance Index that measures the performance of countries based on parameters such as  Greenhouse Gas Emissions, renewable energy, and energy usage.

The 2019 Climate Change Performance Index shows that only Sweden, Morocco, Lithuania, Latvia and the UK have higher rankings according to the parameters. 

Countries that have the lowest rankings are Saudi Arabia, the US, Iran, the Republic of Korea, and Chinese Taipei.

Climate index is a simple calculated value system and diagnostic tool that is used to determine and quantify certain aspects of a geophysical system like the circulation pattern. Also, it is used to describe various states and changes in the climate system. To determine and derive to different indices it applies a variety of methods. Besides, each climate index describes only certain aspects of the climate using specific parameters and each has a defining equation that uses climate elements. These parameters are measurable and these influence the properties of the climate system, mainly, the atmospheric parameters such as air temperature, air pressure, precipitation, and solar radiation, as well as the non-atmospheric parameters like the surface temperature of the sea and the ice cover.

With that, a variety of climate indices have been recorded, examined and defined in different sources and publications. In fact, it was approximately a hundred years ago when the first recorded classical climate indices of the atmosphere have been determined and quantified. One of these is the North Atlantic Oscillation (NAO) which is considered to be the first found teleconnection pattern. Both the NAO index and the NAO pattern can be calculated with the monitoring station data or it can be with the aid of EOF analysis. 

Moreover, these climate indices need a statistical study of a variety of dependent climatological aspects, such as means, extremes, linear trends, comparison of time series, frequency, and statistical analysis. The extreme values and means, standard deviations of time series and linear trends can be quantified for each of these various climate parameters.

Additionally, there are special climate indices that are existing for many parameters. Long-time series of station data are needed to quantify the climate indices for precipitation and air temperature. These results correspond to the chosen station, but in some cases, these are transferable to the dependency on the homogeneity of the environment. Whereas, some results such as the rain events and other minimum temperatures are already in a small space which is highly variable and cannot be transferred to larger areas, easily.

While typical climate indices that use air pressure are on a different type and basis. With these climate indices, the absolute value of a station is not that necessary but it’s the pressure gradient between locations that are needed for the calculation. Hence, it still requires at least two stations but in most cases, field data are being used to calculate atmospheric patterns and long-time series of climate indices. This measure also applies to the sea surface temperature. 

Aside from the atmospheric parameters, the climate index also considers some risk factors due to climate change in different regions of the world that are affected by bad weather conditions such as storms, heatwaves, floods, and others. 

Climate Index Parameters

Air temperature climate indices

Air temperature is the most commonly used atmospheric parameter which measures how hot or cold the air is. Specifically, temperature defines the kinetic or motion energy of the gases that make up the air. It is directly proportional to the gas molecules’ motion, meaning as gas molecules move more quickly, the air temperature also increases. Also, the air temperature is a weather parameter that is recorded since the beginning of weather recording. It is measured daily in 2m height above the ground surface and long-time series existing in different stations. Aside from the current temperature, the daily minimum, and maximum values are also being recorded to be used for the calculation of the indices. 

These include:

  1. number of summer days and tropical nights
  2. Number of frost and ice days
  3. Warm and cold spell duration
  4. Heating degree day
  5. Extreme values during a specific period
  6. Exceeding specific limits (Percentile)
  7. Daily temperature range
  8. Growing season length

Precipitation climate indices

Precipitation is a product of the condensation of atmospheric water vapour that falls on the Earth’s surface, in the form of rain, snow, hail or ice. Its quantities are expressed in millimetres (mm) of liquid water which is equivalent to the preceding time interval. Seemingly, the recording of precipitation amounts also existed during the beginning of weather recording and after several technical developments, even the duration of a precipitation event was also recorded. In addition, the various forms of precipitation (rain, snow, ice) were being collected by the observer and can be detected automatically today.

Moreover, the variation from the mean value of the sum of precipitation at a certain location during a specific time has a significant influence due to drought as a result of low rainfall while heavy rain may be associated with floods. 

The following climate indexes are for the precipitation amount:

  1. Annual total precipitation when the rain rate is above a defined limit (Perzentil)
  2. Annual count of days when the precipitation is greater than a defined limit
  3. Annual total precipitation in wet days
  4. The maximum length of the dry spell
  5. The maximum length of a wet spell
  6. Maximum 1- and 5-day precipitation per Year
  7. Simple precipitation intensity index

Air pressure climate indices

Teleconnection patterns of air pressure are the most commonly use atmospheric parameters by the atmospheric scientists, to calculate climate indices. These teleconnection patterns are withdrawn from the analysis of the sea-level or tropospheric pressure variations on monthly and weekly timescales.

Some of the typical teleconnection patterns are:

  1. North Atlantic oscillation (NAO)
  2. Pacific-North American pattern (PNA)
  3. Arctic oscillation (AO)
  4. Antarctic oscillation (AAO)
  5. Southern Oscillation (SO)

Sea surface temperature climate indices

Sea Surface Temperature (SST) is the measurement of water temperature and motion of molecules on the surface layer of the ocean. The exact definition of the “surface” varies depending on the measurement method used, but typically it is between 1 millimetre (0.04 in) and 20 metres (70 ft) below the sea surface. Also, the spaceborne measurements depend on the type of sensor, which gives us an unprecedented global measurement of sea surface temperatures every week.

These are the climate indices of sea surface temperatures:

  1.  El Niño
  2. La Niña
  3. Atlantic Multidecadal Oscillation (AMO)
  4. Pacific Decadal Oscillation (PDO)
  5. Trends of the Sea surface temperature SST

Global Climate Risk Index 2019

The Global Climate Risk Index 2019 analyzed what countries suffer the most from these extreme weather conditions and to what extent do regions of each country have been affected by the impacts of weather-related loss events such as heatwaves, storms, floods, drought, etc.). From the most recent available data (2017) which is from 1998 to 2017, the countries and regions that are most affected in the year 2017 were Puerto Rico, Sri Lanka and Dominica. Furthermore, from the period of 1998 to 2017, Puerto Rico, Honduras and Myanmar were rank as the highest.

It was recorded that storms, precipitation, floods and landslides were one of the major causes of the damage in the year 2017. Among the ten most affected countries in 2017,  four countries were hit by tropical cyclones. In addition, recent science discovered a clear link between climate change and record-breaking precipitation of hurricanes in 2017. It also claims that the huge number of these severe tropical cyclones will potentially increase as global average temperature increases for every tenth degree.

Additionally, in the same year, it has been recorded that there were more than 526,000 people who died in different regions of the globe due to the occurring more than 11,500 severe weather conditions; and it has been stated that there was almost 3.47 trillion dollars loss between 1998 and 2017 still as a result of frequent extreme weather events.

Reviews about Climate Index

Global Risks Report 2019 by World Economic Forum, What are the biggest risks faced by the world in 2019?

The Global Climate Risk Index 2019: Sri Lanka Ranked Second

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