Monthly Archives: November 2018

Climate multi-model means and anomalies do not reflect physical realities

“A multi-model mean of 81 ensemble members, where the models are all giving wrong answers, some worse than others, simply provides us with a consensus of the wrong answers. And to compound that, the RCP8.5 scenario is, more and more often as days go by, being found to be unrealistic.” click here

No climate trend in hurricane damage losses

Jessica Weinkle, Chris Landsea, Douglas Collins, Rade Musulin, Ryan P. Crompton, Philip J. Klotzbach, Roger Pielke Jr. Normalized hurricane damage in the continental United States 1900–2017. Nature Sustainability (2018)

Direct economic losses result when a hurricane encounters an exposed, vulnerable society. A normalization estimates direct economic losses from a historical extreme event if that same event was to occur under contemporary societal conditions. Under the global indicator framework of United Nations Sustainable Development Goals, the reduction of direct economic losses as a proportion of total economic activity is identified as a key indicator of progress in the mitigation of disaster impacts. Understanding loss trends in the context of development can therefore aid in assessing sustainable development. This analysis provides a major update to the leading dataset on normalized US hurricane losses in the continental United States from 1900 to 2017. Over this period, 197 hurricanes resulted in 206 landfalls with about US$2 trillion in normalized (2018) damage, or just under US$17 billion annually. Consistent with observed trends in the frequency and intensity of hurricane landfalls along the continental United States since 1900, the updated normalized loss estimates also show no trend. A more detailed comparison of trends in hurricanes and normalized losses over various periods in the twentieth century to 2017 demonstrates a very high degree of consistency.

Toxic effects of fluoride on organisms

Huan Zuo, Liang Chen, Ming Kong, Lipeng Qiu, Peng Lü, Peng Wu, Yanhua Yang, Keping Chen. Toxic effects of fluoride on organisms. Life Sciences
Volume 198, 1 April 2018, Pages 18-24

Accumulation of excess fluoride in the environment poses serious health risks to plants, animals, and humans. This endangers human health, affects organism growth and development, and negatively impacts the food chain, thereby affecting ecological balance. In recent years, numerous studies focused on the molecular mechanisms associated with fluoride toxicity. These studies have demonstrated that fluoride can induce oxidative stress, regulate intracellular redox homeostasis, and lead  to  mitochondrial  damage,  endoplasmic reticulum stress and alter gene expression. This paper reviews the present research on the potential adverse effects of overdose fluoride on various organisms and aims to improve our understanding of fluoride toxicity.

Taking a closer look at NCA4; Is RCP8.5 bad science fiction?

Volume I of NCA4 (Climate Science Special Report) features this nifty image of projected global temperatures (°F) for several Representative Concentration Pathway (RCP) scenarios.  RCP2.6 is a drastic mitigation scenario, RCP4.5 is a strong mitigation scenario, RCP8.5 is bad science fiction and often described as “business as usual.”  All the really bad stuff happens in an RCP8.5 world.” click here

Superficial assessment of fluoridation pros and cons

Aoun A, Darwiche F, Al Hayek S, Doumit J. The Fluoride Debate: The Pros and Cons of Fluoridation. Preventive nutrition and food science. 2018 Sep;23(3):171-180. doi: 10.3746/pnf.2018.23.3.171.

Fluoride is one of the most abundant elements found in nature. Water is the major dietary source of fluoride. The only known association with low fluoride intake is the risk of dental caries. Initially, fluoride was considered beneficial when given systemically during tooth development, but later research has shown the importance and the advantages of its topical effects in the prevention or treatment of dental caries and tooth decay. Water fluoridation was once heralded as one of the best public health achievements in the twentieth century. Since this practice is not feasible or cost effective in many regions, especially rural areas, researchers and policy makers have explored other methods of introducing fluoride to the general population such as adding fluoride to milk and table salt. Lately, major concerns about excessive fluoride intake and related toxicity were raised worldwide, leading several countries to ban fluoridation. Health-care professionals and the public need guidance regarding the debate around fluoridation. This paper reviews the different aspects of fluoridation, their effectiveness in dental caries prevention and their risks. It was performed in the PubMed and the Google Scholar databases in January 2018 without limitation as to the publication period.

Fluoride induced genetic alterations, skeletal fluorosis

Daiwile AP, Tarale P, Sivanesan S, Naoghare PK, Bafana A, Parmar D, Kannan K. Role of fluoride induced epigenetic alterations in the development of skeletal fluorosis. Ecotoxicology and environmental safety. 2018 Nov 20;169:410-417. doi: 10.1016/j.ecoenv.2018.11.035.

Fluoride is an essential trace element required for proper bone and tooth development. Systemic high exposure to fluoride through environmental exposure (drinking water and food) may result in toxicity causing a disorder called fluorosis. In the present study, we investigated the alteration in DNA methylation profile with chronic exposure (30 days) to fluoride (8 mg/l) and its relevance in the development of fluorosis. Whole genome bisulfite sequencing (WGBS) was carried out in human osteosarcoma cells (HOS) exposed to fluoride. Whole genome bisulfite sequencing (WGBS) and functional annotation of differentially methylated genes indicate alterations in methylation status of genes involved in biological processes associated with bone development pathways. Combined analysis of promoter DNA hyper methylation, STRING: functional protein association networks and gene expression analysis revealed epigenetic alterations in BMP1, METAP2, MMP11 and BACH1 genes, which plays a role in the extracellular matrix disassembly, collagen catabolic/organization process, skeletal morphogenesis/development, ossification and osteoblast development. The present study shows that fluoride causes promoter DNA hypermethylation in BMP1, METAP2, MMP11 and BACH1 genes with subsequent down-regulation in their expression level (RNA level). The results implies that fluoride induced DNA hypermethylation of these genes may hamper extracellular matrix deposition, cartilage formation, angiogenesis, vascular system development and porosity of bone, thus promote skeletal fluorosis.

US temperature extremes have become more moderate

“Chapter 6 – Temperature Changes in the United States of the U.S. Global Change Research Program’s recently published Climate Science Special Report (2017) clearly shows and discusses, under the heading of “6.1.2 Temperature Extremes”, how temperature extremes for the contiguous United States have become more moderate over the last 118 years, with the coldest daily temperatures warming and the warmest daily temperatures cooling. In other words, temperature-extreme-related climate in the United States has improved.” click here