Cause, conseguenze e strategie di mitigazione Proponiamo il primo di una serie di articoli in cui affronteremo l’attuale problema dei mutamenti climatici. Presentiamo il documento redatto, votato e pubblicato dall’Ipcc - Comitato intergovernativo sui cambiamenti climatici - che illustra la sintesi delle ricerche svolte su questo tema rilevante.

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Climate Change 2007: The Physical Science Basis.

(2008). The implications of projected climate change for freshwater resources and their management. Hydrological Sciences Journal: Vol. 53, No. 1, pp. 3-10.

https://www.tandfonline.com/doi/pdf/10.1623/hysj.53.1.3

The implications of projected climate change for freshwater resources and their management

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Climate change and tropical Andean glaciers: Past, present and future

We assess climate impacts of global warming using ongoing observations and paleoclimate data. We use Earth's measured energy imbalance, paleoclimate data, and simple representations of the global carbon cycle and temperature to define emission reductions needed to stabilize climate and avoid potentially disas- trous impacts on today's young people, future genera- tions, and nature. A cumulative industrial-era limit of ,500 GtC fossil fuel emissions and 100 GtC storage in the biosphere and soil would keep climate close to the Holocene range to which humanity and other species are adapted. Cumulative emissions of ,1000 GtC, sometimes associated with 2uC global warming, would spur ''slow'' feedbacks and eventual warming of 3-4uC with disastrous consequences. Rapid emissions reduction is required to restore Earth's energy balance and avoid ocean heat uptake that would practically guarantee irreversible effects. Continuation of high fossil fuel emissions, given current knowledge of the consequences, would be an act of extraordinary witting intergenerational injustice. Re- sponsible policymaking requires a rising price on carbon emissions that would preclude emissions from most remaining coal and unconventional fossil fuels and phase down emissions from conventional fossil fuels.

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Assessing "dangerous climate change": required reduction of carbon emissions to protect young people, future generations and nature.

. The aim of this paper is to provide the community with a comprehensive overview of the studies of glaciers in the tropical Andes conducted in recent decades leading to the current status of the glaciers in the context of climate change. In terms of changes in surface area and length, we show that the glacier retreat in the tropical Andes over the last three decades is unprecedented since the maximum extension of the Little Ice Age (LIA, mid-17th–early 18th century). In terms of changes in mass balance, although there have been some sporadic gains on several glaciers, we show that the trend has been quite negative over the past 50 yr, with a mean mass balance deficit for glaciers in the tropical Andes that is slightly more negative than the one computed on a global scale. A break point in the trend appeared in the late 1970s with mean annual mass balance per year decreasing from −0.2 m w.e. in the period 1964–1975 to −0.76 m w.e. in the period 1976–2010. In addition, even if glaciers are currently retreating everywhere in the tropical Andes, it should be noted that this is much more pronounced on small glaciers at low altitudes that do not have a permanent accumulation zone, and which could disappear in the coming years/decades. Monthly mass balance measurements performed in Bolivia, Ecuador and Colombia show that variability of the surface temperature of the Pacific Ocean is the main factor governing variability of the mass balance at the decadal timescale. Precipitation did not display a significant trend in the tropical Andes in the 20th century, and consequently cannot explain the glacier recession. On the other hand, temperature increased at a significant rate of 0.10 °C decade−1 in the last 70 yr. The higher frequency of El Nino events and changes in its spatial and temporal occurrence since the late 1970s together with a warming troposphere over the tropical Andes may thus explain much of the recent dramatic shrinkage of glaciers in this part of the world.

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Current state of glaciers in the tropical Andes: a multi-century perspective on glacier evolution and climate change

In the Andes, runoff from glacierized basins is an important element of water budgets, assuring year-round flows for agriculture, potable water, power generation, and ecosystem integrity. Thus, changes induced by tropical glacier retreat constitute an early case of the need for adaptation and the type and size of associated economic and social impacts caused by climate change.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2007EO250001

Economic impacts of rapid glacier retreat in the Andes

The purpose of this report is to provide decision makers in Colombia (and by extension other countries or regions), who are considering the deployment or consolidation of wind power, with a set of options to promote its use. The options presented are the result of an analysis of the Colombian market; this analysis included simulations and modeling of the country's power sector, and extensive consultations with operators, managers, and agents. More information on the analysis and simulations is presented in the appendixes. Wind was chosen to exemplify the range of renewable energy alternatives available to complement traditional power sector technologies on the basis of its technical maturity, its relatively low cost compared to other options, the country's experience, and its wind power potential. This report constitutes the second phase of a barrier analysis to wind energy in Colombia.

Wind Energy in Colombia: A Framework for Market Entry

The objective of the study is to develop a methodology to assess the net impacts of climate change on mountain hydrology. The development of this methodology will allow planners and policy makers to better plan for adaptation measures to address the climate change impacts on the power and water supply sectors. This report presents the methodology used to assess impacts of climate change on mountain hydrology in Peru, and some of the results obtained from employing this methodology. Chapter two presents the method and results of the climate projections (climate analysis). Chapter three presents the hydrologic model (WEAP) and describes how it is modified to take into account the complex mountain hydrological system (hydrology analysis). In chapter four the results of the climate analysis are fed into the modified hydrologic tool to assess future hydrology conditions in selected basins in Peru. Finally, chapter five presents the main conclusions of the study.

Assessment of the Impacts of Climate Change on Mountain Hydrology: Development of a Methodology Through a Case Study in the Andes of Peru

Abstract This paper suggests possible evidence of climate change in Mexico at the watershed level, based solely on historical data. The official Mexican climate dataset was used to find the best set of stations for each watershed. Maximum and minimum temperatures and rainfall in ten watersheds are analyzed from 1970 to 2009. Maximum temperature trends show a significant increment in most of these watersheds. Furthermore, Daily Temperature Range (DTR) exhibits a positive trend (increments), thus implying an increase in temperature extremes. This study also shows that the difference between maximum and minimum monthly temperature trends is negatively correlated with monthly precipitation trends. As a result, land-use and land-cover changes could be the main drivers of climate change in the region.

Possible Climate Change Evidence in Ten Mexican Watersheds

This paper suggests possible evidence of climate change in Mexico at the watershed level, based solely on historical data. The official Mexican climate dataset was used to find the best set of stations for each watershed. Maximum and minimum temperatures and rainfall in ten watersheds are analyzed from 1970 to 2009. Maximum temperature trends show a significant increment in most of these watersheds. Furthermore, Daily Temperature Range (DTR) exhibits a positive trend (increments), thus implying an increase in temperature extremes. This study also shows that the difference between maximum and minimum monthly temperature trends is negatively correlated with monthly precipitation trends. As a result, land-use and land-cover changes could be the main drivers of climate change in the region.

Alejandro Deeb

Papers

Economic impacts of rapid glacier retreat in the Andes

Wind Energy in Colombia: A Framework for Market Entry

Assessment of the Impacts of Climate Change on Mountain Hydrology: Development of a Methodology Through a Case Study in the Andes of Peru

Possible Climate Change Evidence in Ten Mexican Watersheds

Possible climate change evidence in ten Mexican watersheds