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Letter from the Editor | 238

Effects of climate change

By the time this issue appears in print, the 21st United Nations Climate Change Conference (COP21) will have ended.  The Pesquisa FAPESP magazine was in the process of being printed during COP21, which is why this issue does not feature the outcome of what was agreed upon in Paris.  The information, now sorted out and calibrated through the careful analysis of specialized researchers in the field, will appear in the January 2016 issue.  Included here, though, are reports on research projects that are studying the potential consequences of climate change in Brazil.

The first of these is a long-term experiment carried out in the Caxiuanã National Forest in Amazonia.  A team made up of Brazilian and British researchers used 6,000 plastic panels set one to two meters above the soil on a one-hectare parcel of forest to prevent 50% of the rainfall from reaching the ground.  The question they wanted to answer was: how would the forest react if the region were to suffer from a prolonged drought?  In the first few years, the lack of rain did not appear to affect the trees.  But 13 years later, the consequences were visible: the largest trees, some measuring over 40 meters in height, began to collapse, falling victim to the soil dryness.  Only three of the 12 tallest trees, whose diameters exceeded 60 centimeters (cm), are left.  The experiment known as Esecaflor, an abbreviation that means “effects of forest drought,” has already been in place for 15 years and is the most extensive and longest-lasting ever undertaken to evaluate the effects of drought on a tropical forest.

Another project that also has to do with Amazonia dealt with the disastrous combination of fire and drought.  Undertaken by a team from Brazil and the United States, the study evaluated an experiment that used controlled burning in the Upper Xingu, the driest part of the Amazon region.  The results of this study were presented in 2014 and showed that the trees readily resisted the first fire that occurred in 2004.  The greatest damage to the forest took place in 2007 when the controlled burn coincided with a prolonged drought.  The experiment’s planned burn was of such intensity that it destroyed everything in its path.  A combination of less water in the soil, less moisture in the air, dried-out plants and dry weather created a high fire potential, even in regions that are normally moist.

To go along with the report from Amazonia, we also tell you about the economic effects that a rising sea level could bring to the city of Santos, on the coast of São Paulo State, home to Brazil’s main port.  The study includes a discussion of Project METROPOLE, which receives funding from the Belmont Forum, the successor to the International Group of Funding Agencies for Global Change Research (IGFA), bringing together research funding agencies from around the world and supporting studies on issues related to climate change.  Projections regarding a warmer world encompassed two other coastal cities in addition to Santos:  Selsey, a coastal town in southern England, and Broward County, Florida, which includes the city of Fort Lauderdale.

The estimates for the Brazilian city were presented to authorities and the public and, to a certain extent, confirmed what was already known: adaptive actions would greatly reduce the economic losses caused by rising sea levels through 2100.  As an example, in a worst-case scenario, if the sea level rises 45 cm, the damage could come to nearly R$1.3 billion.  With palliative measures – widening beaches, dredging silted-up areas, restoring and preserving mangrove stands and reinforcing seawalls, cumulative losses could be limited to R$200 million over the next eight decades.  Perhaps the main advantage of Project METROPOLE is the fact that it is not limited to science: it involves scientific research, discussion of public policy and participation by the local population.  That is no small matter.

Good reading.