Detection, attribution and natural climate variability
The acknowledge of the past climate to quantify the nature of the changes that are being observed nowadays has been increasing in the last decades as it is presented in the various reports from the Intergovernmental Panel for Climate Change (IPCC 2007). Although the terms “detection” and “attribution” are technically linked, they have distinct objectives. The detection of climate change is a process that uses statistical method to show that climate has changed but it does not discuss the causes of this change. Attribution of the climate change is a process that establishes the most probable cause of the detected change with a determined level of confidence. Attribution as well as detection depends directly on observational data and numerical modeling, in particular for the studies of attribution that have great dependence on climate modeling.
At a general level, a common conclusion in the variety of studies carried out by means of data analysis or simulations using general atmospheric/oceanic circulation models over the past 15 years is that observed climate change cannot be explained exclusively by natural factors; a substantial quantity of anthropogenic influence is necessary to explain the changes. All this evidence highlights the need to study how humans have influenced global climate and contributed to the deviation from natural variability in the terrestrial climate system.
Due to the great potential for environmental impacts suggested by the estimated conditions of future climate, it is extremely important to improve and create new tools allowing detailed evaluation of these impacts in Brazil. These tools are important to provide the scientific bases on which to make decisions about vulnerable regions and processes critical to environmental conservation. Analyses are needed which include ecosystem responses to the climatic forcing at the global scale and a dynamic chain of modifications caused by human occupation, highlighting the most relevant impacts.
Some important Scientific Questions to be answered:
- What are the tendency of the variability observed in the temperature dynamic and precipitation over the past 50 years in Brazil, at the seasonal and medium time scales and in terms of extreme events? What are the causes of this variability and possible tendencies at inter-decadal and long-term time scales?
- How might local and global variability in atmospheric circulation affect the inter-decadal climate variability in Brazil?
- How would the association between extreme climate events and variability in the circulation patterns such as the low level Jet east of the Andes and the SACZ be in the future? How will this configuration be in future climate scenarios?
- How can one recognize the human contributions and natural climate variability in actual climate and in the projections of future climates?
This research should contribute towards a better understanding of weather and climate in Brazil, and their variability at various time scales. It will also serve to support operational meteorologists. Considering the large spectrum of scientific questions to be addressed, the assistance of masters, doctoral and post-doctoral students is fundamental to achieve the desired success. In this way, it is expected that in the short- to medium term, studies developed by these students will help deepen knowledge of climate change in the present and in the long-term, assisting policy makers for mitigation and adaptation to the climate change.