Climate variability in the region and in Brazil overall was discussed at the National Science & Technology Institute on Climate Change conference (photo: mangrove in Guaratiba, Rio de Janeiro / Léo Ramos - Pesquisa FAPESP magazine)
Climate variability in the region and in Brazil overall was discussed at the National Science & Technology Institute on Climate Change conference.
Climate variability in the region and in Brazil overall was discussed at the National Science & Technology Institute on Climate Change conference.
Climate variability in the region and in Brazil overall was discussed at the National Science & Technology Institute on Climate Change conference (photo: mangrove in Guaratiba, Rio de Janeiro / Léo Ramos - Pesquisa FAPESP magazine)
By Diego Freire | Agência FAPESP – According to the latest reports issued by the Intergovernmental Panel on Climate Change (IPCC), one of the consequences of global warming is increasing climate variability, particularly more frequent extremes in terms of very warm and cold weather, floods and droughts.
This assessment is helpful to scientists who are attempting to understand the drought that has occurred in the Southeast of Brazil since the start of summer in 2014, as well as other extreme weather events monitored by the National Science & Technology Institute on Climate Change (INCT-MC), which is funded by the National Council for Scientific & Technological Development (CNPq) and FAPESP.
Researchers at the National Space Research Institute (INPE) and the Natural Disaster Surveillance & Early Warning Center (CEMADEN), both of which are linked to INCT-MC, expect heavy rains and extreme droughts to become more frequent and intense in certain regions of Brazil, especially the South and Southeast.
Their analysis was presented during an international INCT-MC conference held by CEMADEN and INPE on September 28-30 in São Paulo. The event was attended by researchers from some of INCT-MC’s 108 member institutions in Brazil and other countries.
“Climate scenarios produced for South America during the current century point to regional variations in climate change and its impacts. The projections indicate that parts of the north of the American continent will have insufficient rainfall while parts of the southeast will experience much heavier rainfall,” said Tercio Ambrizzi, a researcher affiliated with the University of São Paulo’s Institute of Astronomy, Geophysics & Atmospheric Sciences (IAG-USP).
Ambrizzi’s presentation to the conference, entitled “Observations and attribution of causes of climate variability and extreme weather”, highlighted INCT-MC’s work in this field.
“The IPCC’s latest report shows that global warming is unequivocally happening and presents fresh evidence of the real human contribution to intensification of the greenhouse effect,” Ambrizzi said. “The process of detecting climate change is based on statistical methods and doesn’t discuss its causes. Attributing causes to justify climate change is a process that establishes the most probable cause of the changes detected with a reasonable confidence level.”
With regard to the drought in Southeast Brazil, INCT-MC’s researchers evaluated the dynamic characteristics of extreme periods in the region and their correlations with sea surface temperature (SST) in the South Atlantic, as well as the related synoptic weather patterns, comprising observations of large-scale phenomena such as depressions, cyclones and anticyclones.
Projections of changes in extratropical cyclones deriving from global warming scenarios – based on a range of assumptions for the trajectory of greenhouse gas emissions – suggest that cyclone formation areas near Brazil’s southern coast will move southward between 2071 and 2085, affecting atmosphere blocking patterns over the subtropics and potentially causing droughts in several agricultural zones of Brazil.
“The link between extreme droughts occurring in the Southeast of Brazil in fall, winter and spring and sea surface temperature anomalies in the South Atlantic isn’t well understood,” Ambrizzi said. “We therefore conducted detection work to determine the dates of these events for five regions in the period 1982-2009. The synoptic and dynamic characteristics of these periods were investigated by analyzing SST anomalies, humidity sources, and the behavior of cold fronts in South America, among other elements.”
The number of dry events was highest during the winter, followed by fall and spring. In terms of location, the highest number occurred in the northern portion of the Southeast, and these were also the longest, lasting 117 days on average. Dry events in the southern portion of the region were fewer in number as well as shorter, lasting at most 30 days. The middle of the region could be considered a transition zone.
Cold fronts tend to be concentrated in the south of South America, research also shows.
Integrating themes
INCT-MC’s international conference also featured presentations about research and projections relating to greenhouse gas emissions and the impact of climate change on coastal zones and oceans, natural disasters, biodiversity, health, and energy, water and food security, among other topics.
“This is an ambitious scientific enterprise, which aims to provide information of high quality and relevance that’s indispensable for Brazil to achieve the goals of its National Climate Change Action Plan,” said Carlos Afonso Nobre, coordinator of INCT-MC, during the opening ceremony.
Marina Silva, a former senator and former environment minister of Brazil, delivered the keynote address. Also attending the ceremony were Ricardo Magnus Osório Galvão, director of INPE; Osvaldo Luiz Leal de Moraes, director of CEMADEN; José Antonio Marengo, head of CEMADEN’s research division; Reynaldo Luiz Victoria, coordinator of FAPESP’s Global Climate Change Research Program (RPGCC); Roberto Muniz Barretto de Carvalho, representing the National Scientific & Technological Development Council (CNPq); Márcio Rojas from the Ministry of Science, Technology, Innovation & Communications (MCTIC); and Moacyr Cunha Araujo Filho, coordinator of the Brazilian Global Climate Change Research Network (Rede CLIMA).
More information at www.fapesp.br/eventos/inct.
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