Which Of The Following Is The Best Indicator Of Recent Climate Change?

Climate Modify indicators are observations that tin can be used to track the electric current state of climate and its trends.

Climate is defined equally the average weather weather prevailing at a place or a region over a long catamenia. At a broader scale climate systems include land, atmosphere, ocean and the cryosphere. The World Meteorological Organisation (WMO) specifies a period of 30 years to ascertain the climate of a place.

Climate is non static. It exhibits both brusque term variability as well as changes over a long period of time. Variation in climate from 1 year to another is known every bit natural variability. Drought in one year and floods in another is a part of natural variability. Changes in atmospheric condition elements and the climate system observed over a long period of time is called climate change.

The earth'due south climate has changed throughout history. In the concluding 650,000 years in that location have been cycles of glacial accelerate and retreat, with an abrupt cease of the concluding water ice historic period most xi,000 years ago. It marked the beginning of the modern climate era and of homo civilization. Nigh of these climate changes are attributed to very small variations in earth's orbit that change the amount of solar energy received by the Earth. These climate changes used to take place over a very long period spread over thousands of years. The current warming trend is of significance because most of it is acquired by human activity since the mid-20th century and proceeding at a rate unprecedented.

Climate Change Indicators

Climatic change indicators are observations that can be used to rails the electric current state of climate and its trends. In society to bring objectivity in monitoring climate change, scientists take adult climate change indicators. The indicators are quantified and objective, based on data collected by countries all over the world. An indicator is selected based on its relevance, representativeness, traceability, timeliness and data adequacy.

Climate change indicators may be physical, ecological, or societal. These help in monitoring how climatic atmospheric condition are changing and to appraise risk and vulnerabilities. Depending on areas of awarding, number and type of indicators tin vary from every bit many as 40 indicators monitored by the United States Environment Agency (USEPA). These cover greenhouse gases, weather and climate, oceans, snow and water ice, wellness and rubber and ecosystems (USEPA 2016).
The primary focus of meteorologists is to detect and predict physical components of the climate system. The WMO has identified six principal indicators (WMO 2017):

1. Global annual average surface temperature
2. Atmospheric concentrations of carbon dioxide
3. Ocean oestrus content
4. Global hateful sea level
5. Mass of the cryosphere or Global extent
6. Global precipitation

The Agenda 2030, adopted by the United nations in 2015, seeks to use indicators to track progress on the Sustainable Development Goals, including SDG13 on combating climate change and its impacts. The Parties to the United nations Framework Convention on Climate Change (UNFCCC) are as well likely to include indicators in the five yearly 'global stocktake' for measuring progress under the Paris Agreement.

ane. Global temperatures as a climate modify indicator

The yr 2019 was the second warmest yr in the 140 yr record, with a global land and ocean surface temperature divergence from average of +0.95°C (NOAA 2019). This value is simply 0.04°C less than the tape high value of +0.99°C gear up in 2016 and 0.02°C higher than the now third highest value set in 2015 (+0.93°C ).

The five warmest years in the 1880–2019 record have all occurred since 2015, while ix of the 10 warmest years have occurred since 2005. The yr 1998 currently ranks as the 10 warmest, the simply twelvemonth earlier 2005 that made it to the tape.

Subsequently that, the year 2019 marks the 43rd sequent yr (since 1977) with global state and sea temperatures, at to the lowest degree nominally, to a higher place the 20th century average indicating the tedious but steady ascension of a changing climate. This yr (2019) began in a weak-to-moderate El Niño, transitioning to El Niño–Southern Oscillation (ENSO)-neutral conditions past July. During the year, each monthly temperature ranked among the five warmest for their respective months on record, with the months of June and July recording warm.

The global annual temperature has increased at an average charge per unit of 0.07°C per decade since 1880 and over twice that rate (+0.18°C) since 1981; surface air temperature anomaly for the year 2019 is shown in Fig one.

Fig 1 : Surface air temperature anomaly for 2019 with respect to the boilerplate 1981-2010 ( Source : European Centre for Medium Range Weather Forecast ERA5 data)

ii. Atmospheric concentration of greenhouse gases: A tell-tale climatic change indicator

Increasing levels of greenhouse gases in the atmosphere are a major driver of climate change. Atmospheric concentrations reflect a remainder between sources (including emissions) and sinks. Global carbon dioxide (CO2) concentrations reflect the balance between emissions due to human activities and uptake by the biosphere and ocean.
The WMO report on greenhouse concentration shows that 2015-2019 has seen continued increment in CO2 and other greenhouse gases in the atmosphere (Fig two). CO2 growth rates are nearly xx per cent higher than the previous five years. CO2 remains in the atmosphere for centuries and in the sea for an even longer period.

In 2018, greenhouse gas mole fractions reached new highs, with globally averaged mole fractions of CO2 at 407.8±0.1 ppm, CH4 at 1869±2 ppb and N2O at 331.1±0.1 ppb (Fig. 2). The almanac increases in the three master greenhouse gases were larger than the increases in the previous year and the ten-yr averaged growth rates. The global averaged mole fractions in 2018 institute, respectively, 147, 259 and 123 per cent of pre-industrial (1750) levels. Global average figures for 2019 will not be bachelor until late 2020, only real-time data from specific locations, including Mauna Loa (Hawaii) and Cape Grim (Tasmania) indicate that levels of CO2, CH4 and N2O continued to increase in 2019. Latest March 2020 CO2 observation reported by Mauna Loa Observatory is 414.5 ppm.

Effigy 2: Globally averaged concentration of CO2 from 1984 to 2018

3. Sea level rise:

Sea level rise is one of the less visible climatic change indicators but a very reliable one. Over the five-year period May 2014 -2019, the rate of global mean sea-level rise has amounted to 5 mm per year, compared with 4 mm per yr in the 2007-2016 ten-year period. This is substantially faster than the average rate since 1993 of 3.2 mm/year. The contribution of land water ice melt from the world glaciers and the ice sheets has increased over fourth dimension and now dominate the sea level budget, rather than thermal expansion.

In 2019, the bounding main level continued to rise (Fig 3), with the global mean ocean level reaching its highest value since the get-go of the high-precision altimetry record (January 1993). The average rate of rise is estimated at 3.24 ± 0.iii mm year–one over the 27 yr period, but the charge per unit has increased over that fourth dimension. A greater loss of ice mass from the ice sheets is the main cause of the accelerated rise in the global mean bounding main level on acme of steady increases from the expansion of ocean waters driven past warming due to climatic change.

Figure iii: Global hateful sea level evolution from January 2016 to 2019 from loftier precision altimetry.

4. Ocean Heat Content

The bounding main is an of import part of the Globe system. The rate of modify in ocean heat content is a measure of global warming and a robust climate change indicator, every bit it represents a large proportion of the heat accumulating in the climate system.

Thermal expansion from body of water warming, combined with melting of ice on country, leads to bounding main level rise, which affects coastal areas. Changes in ocean chemistry associated with rise CO2 concentrations in the atmosphere are altering the pH of the oceans. Ocean heat content (OHC) is a central metric for climate change as it is a measure out of heat accumulation in the globe system.

Human-induced atmospheric composition changes cause a radiative imbalance at the elevation of the temper – earth's energy imbalance – which is driving global warming and climate alter. Due to the ocean's large heat capacity, the bulk (~90 per cent) of this accumulated heat is stored in the global ocean. Consequently, the ocean is warming, with wide-reaching impacts on the globe climate organization.

For example, OHC increase contributes more than 30 per centum of observed global hateful sea-level rise through thermal expansion of sea water. Ocean warming is altering sea currents, and indirectly altering the storms.

The yr 2018 had the largest ocean heat content values on record measured over the upper 700 meters, with 2017 ranking second and 2015 3rd (Fig 4). The ecological costs to the ocean, however, are loftier, as the captivated CO2 reacts with seawater and changes the acerbity of the ocean. At that place has been an overall increase in acidity of 26 per cent since the beginning of the industrial revolution.

Fig 4: Ocean Heat Potential

five. Mass of the cryosphere or g lobal extent : Inversely related to climate change

Throughout 2015-2018, the Arctic's average September minimum (summertime) body of water-ice extent was well below the 1981-2010 average, as was the boilerplate winter sea-ice extent (Fig 5).

The four lowest records for winter occurred during this period. Multi-year ice has about disappeared. Antarctic'south February minimum (summer) and September maximum (wintertime) bounding main-ice extent values take become well below the 1981-2010 boilerplate since 2016. This is in dissimilarity to the previous 2011-2015 period and the long term 1979-2018 period.

Antarctic summertime sea ice reached its lowest and second lowest extent on record in 2017 and 2018, respectively, with 2017 also being the 2nd lowest winter extent. The amount of ice lost annually from the Antarctic ice canvass increased at least six-fold, from 40 Gt per year in 1979-1990 to 252 Gt per yr in 2009-2017.

The Greenland water ice canvas has witnessed a considerable acceleration in ice loss since the turn of the millennium. The World Glacier Monitoring Service (WGMS) reference glaciers indicates an average specific mass alter of −908 mm water equivalent per year during 2015-18, higher than in all other five-year periods since 1950. These are glaring climatic change indicators that show the rapidity with which changes are taking identify.

Fig 5: Monthly September and March Arctic sea-ice extent anomalies (relative to the 1981–2010 average) for 1979– 2019
Sources: US National Snow and Ice Data Center (NSIDC) and EUMETSAT Bounding main and Body of water Ice Satellite Application Facility.

6. Global Precipitation Patterns as a Climatic change Indicator

Unusually dry conditions in relation to long-term ways for 2019 were observed in Australia and western Republic of indonesia and surrounding countries. Also, southern Africa, Central America and parts of South America received abnormally depression precipitation amounts. Large areas with unusually high precipitation amounts were observed in the Primal United States, Northern Canada, northern Russia, South-west Asia, northern China and eastern Africa.

There was a large precipitation deficit in India in June as the onset of the monsoon was delayed. Still, associated with the positive IOD phase, the withdrawal of the Indian monsoon was besides delayed and there was an excess of precipitation in the post-obit months for all regions except due north-eastward India. In add-on, positive precipitation anomalies in eastern Africa and negative anomalies in the Malay Archipelago and Australia are associated with the positive IOD phase, which prevailed through most of the second half of 2019. This unpredictable change in precipitation levels is withal another indication of climate change.

7. Extreme events and Climate Change

Hydro-meteorological hazards account for more ninety per cent of the natural disasters. The dominant disasters are storms and flooding, which have as well led to highest economic losses. Heatwaves and drought have led to human being losses, intensification of forest fires and loss of harvest. These extreme events are climate change indicators that exhibit the stress under which ecosystems lie.

viii. Heat Waves : Hallmark climatic change indicator

Heat waves, which were the deadliest meteorological take a chance in the 2015-2019 menses, affecting all continents and resulting in numerous new temperature records. Almost every study of a meaning estrus wave since 2015 has found it to exist the hallmark of climate change. The year 2019 also saw numerous major heat waves.

Amid the almost pregnant were two heat waves that occurred in Europe in late June and late July (Fig 16). The start i reached its maximum intensity in southern France, where a national record of 46.0 °C (1.nine °C higher up the previous record) was set on 28 June at Vérargues (Hérault). Japan experienced 2 heat waves that were notable in unlike ways.

The get-go occurred in late May, with unusually loftier temperatures, including 39.5 °C (the equal highest on tape for whatever time of year on the island of Hokkaido), but limited impacts.

The 2nd, in July, was less unusual in a meteorological sense merely had much greater wellness impacts as it occurred during the summit of summer and was focused in the more than heavily populated surface area of Honshu. Australia had an exceptionally hot summertime in 2018–2019. The mean summer temperature was the highest on record past almost one °C, and January was Australia'due south hottest calendar month on record.

Most of the country was affected. The occurrences of estrus waves in hitherto unaffected regions are deeply concerning and once once more global warming due to climatic change is to be blamed.

9. Tropical Cyclones: A significant climate change indicator

The largest economic losses were associated with tropical cyclones. The 2017 Atlantic hurricane flavor was 1 of the nearly devastating on tape with more 125 billion USD in losses associated with Hurricane Harvey alone. On the Indian Ocean, in March and April 2019, unprecedented and devastating back-to-back tropical cyclones hit Mozambique. Global tropical cyclone activity in 2019 was above average.

The northern hemisphere had 72 tropical cyclones, compared with the average of 59. The 2018–2019 southern hemisphere season was likewise above average, with 27 cyclones, the highest number in a flavor since 2008–2009. It was a specially extreme cyclone season in the N Indian Body of water.

3 cyclones reached maximum sustained winds of 100 kn or more, the outset known instance in a single season, and the seasonal ACE was the highest on record by a large margin. Fani was the well-nigh significant cyclone to affect India since 2013, making landfall in the eastward, on the Odisha declension, on May 3, with sustained winds of 100 kn, having earlier peaked at 135 kn in the Bay of Bengal.

In that location was significant damage in coastal areas and loss of life, although extensive evacuations in affected coastal areas greatly reduced the homo impact. Kyarr, in October, was 1 of the strongest cyclones on record in the Arabian Sea, only did not make landfall, although associated loftier seas and tempest surges afflicted some coastal areas.

x. Wildfires: Major influencer as a climate change indicator

Wildfires are strongly influenced past weather and climate phenomena with global warming due to climate change being one of the major influencers. Drought substantially increases the risk of wildfire in most wood regions, with a particularly strong influence on long-lived fires. The iii largest economic losses on record from wildfires have all occurred in the last four years.
In many cases, fires have led to massive releases of carbon dioxide to the temper. Summer 2019 saw unprecedented wildfires in the Arctic region. In June lonely, these fires emitted l megatons (Mt) of carbon dioxide into the temper. This is more than that released by Arctic fires in the same month from 2010 to 2018 put together. There were too massive forest fires in Canada and Sweden in 2018. Also significant were widespread fires in the tropical rain forests in Southern asia and Amazon, which have had impacts on the global carbon budget. The Australian bushfire of 2019-20 occurred in the summertime of 2019, Australia's hottest on record thereby linking the result with climatic change.

Mode forwards

Ongoing tendency in the rising of global average temperature due to climate alter continued in 2019, with a global average temperature of 1.1oC above estimated pre-industrial (1850-1900) averages. The year 2019 was besides the 2nd warmest year. In 2018-xix, greenhouse gases concentration reached new highs. Latest March 2020 observation of CO2 reported by Mauna Loa Observatory is 414.five ppm. Increasing levels of greenhouse gases in the atmosphere are a major driver of climate modify.

Forth with rise in temperature and increment in greenhouse gases, other climate change indicators too confirm the ongoing tendency of climate change. Bounding main levels are rising at an increasing pace through greater warming of oceans both at the surface and in the depths. Enhanced melting of Greenland's ice and of glaciers also contributing to body of water level rise. It is exposing coastal areas and islands to flooding and the submersion of depression-lying areas. The year witnessed severe Oestrus Waves in Europe, Japan and Australia. Heat waves combined with prolonged drought led to wildfires of unprecedented size in Australia, Siberia and Arctic regions. In line with global trends, India as well experienced above boilerplate temperatures, rainfall, cyclonic storms in 2019. These climate change indicators are nature'southward fashion of indicating that our planet is under stress and needs firsthand remedial action to prevent a global catastrophe.

References:

1. Us Environmental Protection Agency (United states EPA). 2016. Climate change Indicators in the United States 2016: United states EPA, Washington D.C.: United States. Bachelor at: http://www.epa.gov/climate
2. World Meteorological Organisation (WMO). 2017. Weather ready, Climate smart – Supporting the 2030 Agenda for Sustainable Evolution: WMO, Geneva: Switzerland. Available at: https://library.wmo.int/doc_num.php?explnum_id=3997
iii. National Centers for Environmental Information (NCEI). 2019. Land of the Climate – Global Climate Report for Annual 2019: NCEI, N Carolina: U.s.a.. Available at: https://world wide web.ncdc.noaa.gov/sotc/global/201913