IPCC Sres Revisited: A Response

Abstract

Mr. Castles and Mr. Henderson have criticized the Special Report on Emissions Scenarios (SRES) and other aspects of IPCC assessments. It is claimed that the methodology is “technically unsound” because market exchange rates (MER) are used instead of purchasing power parities (PPP) and that the scenarios themselves are flawed because the GDP growth in the developing regions is too high. The response is: The IPCC SRES reviews existing literature, most of which is MER based, including that from the World Bank, IEA and USDoE. Scenarios of GDP growth are typically expressed as MER (the preferred measure for GDP growth, as opposed to PPP which is a preferred measure for assessing differences in economic welfare). IPCC scenarios did include PPP-based scenarios, which Mr. Castles and Mr. Henderson have conveniently ignored. Contrary to what Mr. Castles and Mr. Henderson claim, IPCC scenarios are consistent with historical data, including that from 1990 to 2000, and with the most recent near term (up to 2020) projections of other agencies. Long-term emissions are based on multiple, interdependent driving forces, and not just economic growth. Mr. Castles and Mr. Henderson need to look beyond GDP. The IPCC scenarios provided information for only four world regions, and not for specific countries. Mr. Castles' and Mr. Henderson's critique is not of IPCC scenarios but of ongoing unpublished work in progress that is not part of SRES. We therefore show that Mr. Castles and Mr. Henderson have focused on constructing a “problem” that does not exist. SRES scenarios are sound and the IPCC has responded seriously and conscientiously. We detail our response below in nine sections. After an introduction (Section 1), we outline the SRES methodology for measuring economic output (Section 2). Section 3 compares SRES to long-historical economic development and provides five responses to the critics. Section 4 addresses the issue of country-level economic projections even if not part of SRES. Sections 5, 6 and 7 validate the SRES scenarios by comparing them with recent trends for economic and CO2 emission growth, as well as more recent scenarios available in the literature. Section 8 refutes the argument that lower economic growth in developing countries would lower GHG emissions correspondingly. Section 9 concludes.

Combining Satellite Data and Models to Assess Vulnerability to Climate Change and Its Impact on Food Security in Morocco

“…We extend this model to include the impact of climate (C) through changes in temperature and precipitation and their impact on the NPP supply, such as I = PATC. We elect to perform a quantitative assessment of the aggregated impact of these factors on the NPP demand and supply under two of the IPCC Special Report on Emissions Scenarios (SRES), A2 and B2 [34], and compare it to the 2007 baseline.…”

“…The level of technology is related to efficiencies in harvest and crop residue left on the ground, efficiencies in wood processing and transport and an increase in the level of recycling, which, in our calculation, represent the aggregate technological development indicator (Te) of the country. Furthermore, and for consistency, we have considered for Morocco the average annual population growth rate used in the IPCC scenarios [34]. Finally, for affluence, we have assumed that under A2, by 2025, the per capita appropriation in Morocco will double with respect to that of 2007, whereas for B2, we have estimated the per capita appropriation from the actual rate of change computed over the period 1995-2007 and extended it to 2025.…”

Climate Change in the Himalayas: Current State of Knowledge

“…The Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR4) presents temperature and precipitation projections for South Asia, derived from a dataset of 21 GCMs, suggest a median increase of 3.3 °C by 2100 for the A1B SERS scenario (a ''middle of the road'' estimate of future conditions; Nakićenović et al, 2000), with increases in both daily minimum and maximum temperatures (Christensen et al, 2007). As Christensen et al (2007) point the largest warming is expected on the Tibetan Plateau and the higher-altitude Himalayan regions: 3.8 °C during the next 100 years.…”

Integrated scenarios for energy: A methodology for the short term

“…This is dependent on the evolution of human factors such as anthropogenic GHG emissions. Given the uncertainty of future development, scenarios were used in the Special Report on Emission Scenarios (SRES) of the Intergovernmental Panel on Climate Change (IPCC) as the appropriate tool for the exploration of the future evolution of global GHG emissions to 2100 [18]. As many social and biophysical systems are complex in evolution and poorly understood, the scenarios were neither predictions nor forecasts but were used to explore equally plausible images of future development.…”