Climate evolution and projections for Chile announced

The Environment Ministry has announced how Chile’s climate is expected to evolve, as well as future projections and the multiple implications of climate change, from the offices of the country’s Meteorological Department. 

As expected, the increase in temperature has been a key factor in the different impact chains, to the extent that 2021 was the fourth hottest year in more than half a century. The trends show an expected 0.15°C rise per decade. In fact, the last 11 years have been the hottest on record. 

Temperatures above 30°

The maximum temperature is the indicator that has increased most rapidly. We have one more week of temperatures above 30°C every 10 years, which has made the duration and intensity of heat waves intensify. They have doubled in the last 20 years. 

0° Isotherm  

The height of the 0° isotherm has also been an important indicator to monitor. Its height has increased by almost 40 meters/decade and 60 meters/decade in the last two decades in Antofagasta. 

Another piece of climate change evidence that has been of concern for several years is precipitation. In the north of the country, an increase in precipitation events has been observed, especially in summer-autumn, with an increase of 20 to 40% per decade. 

In the central, southern and extreme southern zones, there is evidence of a decrease in precipitation, which has been a determining factor in the drought the area is facing. In 2021, we experienced the wettest summer and the driest winter. 

The decrease at the national level is 26 mm/decade. That is a drop of 4% every 10 years, which doubles to 8% if we consider the last 40 years. We have currently had 13 consecutive years of below-normal precipitation, and 2022 can be added to this sequence of dry years. 

Projections 

The Climate Risk Atlas (ARClim) is an Environment Ministry tool, developed by the Center for Climate and Resilience Research (CR2) and the Center of Global Change (CCG – Universidad Católica de Chile), with the collaboration of other regional, national and international institutions. 

Thanks to ARClim, it has been possible to project the panorama in Chile for the coming years: 

• Hot days above 30°C 
• ARClima definition: Number of days in which the maximum temperature exceeds 30°C. 
• It is projected that the total number of days above 30°C will increase by 20 days or more in 103 municipalities in Chile. 
• It is projected that the increase in days above 30°C will be 30 days or more in 45 municipalities. 
• It is projected that municipalities in the central valley of the Metropolitan, O’Higgins and Maule regions will experience at least 80 days a year with temperatures above 30°C in the future. 
• It is projected that municipalities such as Quilicura, Lo Prado, Cerro Navia, Cerrillos, Renca and Lo Espejo will experience more than 100 days a year above 30°C in the future. 

Drought frequency 

ARClim definition: Frequency of periods in which accumulated precipitation is less than 75% of the average accumulated precipitation in the reference period (1980 to 2010). 

• It is projected that in the future (2035-2065) drought frequency in a large part of the Chilean territory will increase, especially between the Atacama and Aysén regions. 
• It is projected that 180 municipalities will experience 40% or more drought frequency in the future, above all in the Coquimbo, Valparaíso, Metropolitan, O’Higgins and Maule regions. 
• It is projected that the increase in drought frequency – the difference between the present and the future – will be more than 20% in 122 municipalities (Valparaíso 18; Metropolitan 17; O’Higgins 28; Maule 30; Ñuble 15). 

Accumulated precipitation 

ARClim definition: Amount of accumulated precipitation (rain and snow). 

• It is projected that accumulated precipitation will decrease in much of the country between the Atacama and Aysén regions. 
• It is projected that this decrease will be between 16 and 17% between the Coquimbo and Ñuble regions. 

Accumulated snowfall 

ARClim definition: Amount of accumulated snowfall, expressed in mm of equivalent water. 

• It is projected that accumulated snowfall will considerably decrease throughout the national territory. 
• It is projected that accumulated snowfall will decrease from 403mm per year in the present to 252mm per year in the future in the municipality of San José de Maipo, Metropolitan Region. 
• It is projected that accumulated snowfall will decrease by more than 50% in all Andean municipalities in the O’Higgins, Maule, Ñuble, Biobío, La Araucanía and Los Lagos regions. 

Beach erosion 

Studies commissioned by the Environment Ministry show the erosion of Chile’s beaches, which have been impacted by extreme events such as rising tides. 

The study analyzed a total of 35 beaches, 28 of which showed erosion and high erosion. Erosion is defined as the retreat of the coastline and is measured in meters per year (m/year). Erosion is said to be high when the retreat of the coastline is greater than 1.5m/year, while normal erosion is said to be between 0.2m/year and 1.4m/year. 

The beaches with the highest rates of damage are Hornitos (Antofagasta Region), Algarrobo and Santo Domingo (Valparaíso Region), and Pichilemu (O’Higgins Region). The study also indicated that the highest rates of erosion are seen in cove beaches with extensive sandy coastlines, related to old dune fields and coastal wetlands.