Climate Sensitivity

Abstract. Recruitment algorithms in forest gap models are examined with particular regard to their suitability for simulating forest ecosystem responses to a changing climate. The traditional formu-lation of recruitment is found limiting in three areas. First, the aggregation of different regeneration stages (seed production, dispersal, storage, germination and seedling establishment) is likely to result in less accurate predictions of responses as compared to treating each stage separately. Second, the related assumptions that seeds of all species are uniformly available and that environmental conditions are homogeneous, are likely to cause overestimates of future species diversity and for-est migration rates. Third, interactions between herbivores (ungulates and insect pests) and forest vegetation are a big unknown with potentially serious impacts in many regions. Possible strategies for developing better gap model representations for the climate-sensitive aspects of each of these...

Nonlinear regression is a useful statistical tool, relating observed data and a nonlinear function of unknown parameters. When the parameter-dependent nonlinear function is computationally intensive, a straightforward regression analysis by maximum likelihood is not feasible. The method pre-sented in this paper proposes to construct a faster running surrogate for such a computationally intensive nonlinear function, and to use it in a related non-linear statistical model that accounts for the uncertainty associated with this surrogate. A pivotal quantity in the Earth’s climate system is the climate sen-sitivity: the change in global temperature due to doubling of atmospheric CO2 concentrations. This, along with other climate parameters, are estimated by applying the statistical method developed in this paper, where the computa-tionally intensive nonlinear function is the MIT 2D climate model. 1. Introduction. A fundamental question in understanding the Earth’s cli-mate system is quan...

Little is known concerning the effects of wildfires on tree radial growth and their climatic response under contrasting regimes of fog water inputs on oceanic islands. On Tenerife, Canary Islands, windward slopes are humid with high-fog frequency due to influence of wet trade winds, while climate on leeward slopes is more arid. We used tree-ring records of Pinus canariensis Sweet ex Spreng. to quantify the effects of a fire of known date on radial growth and determine the main limiting climatic factors for growth. Radial growth patterns and their responsiveness to fire severity and climatic variation differed between windward and leeward slopes. Surface fire did not significantly impact growth, while crown fire caused short-term growth reduction, and even cessation, more pronounced on the windward slope. Growth rates, tree-ring common signal, and climate sensitivity were smaller on the windward slope, with cold winters, and summer water stress limiting growth. On the leeward slope, climate explained a greater amount of growth variation mainly due to negative effects of high October–December sea-level pressures causing dry winter conditions. Contrasting growth dynamics on both slopes may result from diverging physiological effects of water inputs and reduced radiation caused by fog drip. Our findings suggest that dating growth suppressions and absent rings are useful to date past high-severity crown fires in P. canariensis forests, in addition to ordinary fire scars dating indicative of low-severity surface fires.

Monthly means of Mauna Loa atmospheric CO2 are used in conjunction with surface temperature data from two different sources for sample periods 1959-2017 and 1979-2017 to estimate observed Charney climate sensitivity (ECS) for each of twelve calendar months and five regions. Significant differences among regions and calendar months are found but with close agreement between the two temperature datasets except for land surfaces in the Northern Hemisphere. The results suggest that the Hadley Center land surface temperature reconstruction for the Northern Hemisphere contains anomalies. Other than land in the Northern Hemisphere, the observational estimates of regional mean Charney climate sensitivities are low. They range from 1.23 to 2.00 for sea surfaces, 2.32 to 2.35 for land surfaces, and 1.88 to 1.97 for all surfaces combined 1 .

The tourism sector is one of the largest and fastest growing global industries and is a significant contributor to national and local economies around the world. The interface between climate and tourism is multifaceted and complex, as climate represents both a vital resource to be exploited and an important limiting factor that poses risks to be managed by the tourism industry and tourists alike. All tourism destinations and operators are climate-sensitive to a degree and climate is a key influence on travel planning and the travel experience. This chapter provides a synopsis of the capacities and needs for climate services in the tourism sector, including current and emerging applications of climate services by diverse tourism end-users, and a discussion of key knowledge gaps, research and capacity-building needs and partnerships that are required to accelerate the application of climate information to manage risks to climate variability and facilitate successful adaptation to climate change.

ABSTRCT: Although the science of the greenhouse effect of atmospheric CO2 is well established, all efforts to relate this phenomenon to fossil fuel emissions has failed because of deficiencies in the methodology used in the presentation of empirical evidence. Circular reasoning is used in the IPCC carbon budget to relate atmospheric CO2 to fossil fuel emissions as a way of dealing with insurmountable measurement problems. No evidence exists to relate changes in atmospheric CO2 or the rate of warming to fossil fuel emissions because correlations presented for these relationships are spurious. The UNFCCC holds annual COP meetings and calls for reductions in fossil fuel emissions to attenuate global warming without evidence that warming is related to emissions 1. 1. CIRCULAR REASONING IN THE IPCC CARBON BUDGET The so called Carbon Budget, published periodically by the IPCC and also by the Global Carbon Budget (GCB) project (LeQuere, 2015) (IPCC, 2014), is an accounting balance that reconciles all flows of carbon dioxide between the atmosphere and the surface of the earth, both land and ocean. This accounting balance plays a foundational and pivotal role in the Anthropogenic Global Warming (AGW) hypothesis. The AGW argument holds that fossil fuel emissions generated by the mechanized civilization of the post Industrial Revolution world has increased atmospheric carbon dioxide concentration; and that higher CO2 levels in the atmosphere have, in turn, increased its greenhouse effect that in turn increases the earth's surface temperature which, if unchecked, will cause Catastrophic Climate Change (CCC) (IPCC, 2014) (Hansen, 1981) (Lacis, 2010). Bias and circular reasoning in the IPCC and GCB carbon budget procedures arise because a presumption of this scenario influences the way the flow accounting is carried out. In the IPCC terminology of carbon budgets, flows from the surface to the atmosphere are called sources and those from the atmosphere to the surface are called sinks. The flows are enumerated in petagrams (10 15 grams) or gigatons (10 9 metric tons) of carbon equivalent flow per year. The two metrics have the same numerical value. Since the molecular weight of carbon dioxide is 44 and that of carbon is 12, the actual flow of carbon dioxide is 3.667 times the carbon equivalent flows quoted. Seven flows are recognized by the IPCC in Chapter 6 of the AR5 WG1 (IPCC, 2014). They are listed in Figure 1 where sources are identified as R and sinks as N. The accounting balance, or carbon budget, is that a change in atmospheric CO2 in terms of carbon equivalent (ΔC) = the difference between sources and sinks. This relationship may be written as ΔC = ∑R-∑N or ∑R-∑N – ΔC = 0. The values for these flows in gigatons of carbon equivalent per year (GTCY) provided by the IPCC are tabulated in Figure 1. 1 Date: December 2016, with thanks to @dumbsci for constructing the research question

Homicides in England and Wales 1898-2003 are studied against the atmospheric carbon dioxide data for the same period. The Charney Equilibrium Sensitivity of homicides is found to be λ=1.7 thousands of additional annual homicides for each doubling of atmospheric CO2. The sensitivity estimate is supported by a strong correlation of ρ=0.95 and detrended correlation of ρ=0.86. The analysis illustrates that spurious proportionalities in time series data in conjunction with inadequate statistical rigor in the interpretation of empirical Charney climate sensitivity estimates impedes the orderly accumulation of knowledge in this line of research 1 .

The temperature on Earth varied largely in the Pleistocene from cold glacials to warmer than present interglacials. To contribute to an understanding of the underlying causes of these changes we compile various environmental records (and model-based interpretations of some of them) in order to calculate the direct effect of various processes on Earth's radiative budget and, thus, on global annual

Detrended correlation analysis of global mean temperature observations and model projections are compared in a test for the theory that surface temperature is responsive to atmospheric CO2 concentration in terms of GHG forcing of surface temperature implied by the Climate Sensitivity parameter ECS. The test shows strong evidence of GHG forcing of warming in the theoretical RCP8.5 temperature projections made with CMIP5 forcings. However, no evidence of GHG forcing by CO2 is found in observational temperatures from four sources including two from satellite measurements. The test period is set to 1979-2018 so that satellite data can be included on a comparable basis. No empirical evidence is found in these data for a climate sensitivity parameter that determines surface temperature according to atmospheric CO2 concentration or for the proposition that reductions in fossil fuel emissions will moderate the rate of warming. 1