The severity of the world’s climate change issue has long been underestimated by many. According to the Environmental Protection Agency, “Climate change refers to any significant change in the measures of climate lasting for an extended period of time”.1 From 1880 to 2012, the annual temperature of the globe has increased by 1.5 F (0.8 C). 2 The numbers may seem small, but the impact is drastic. In fact, the world is currently experiencing the warmest temperatures to date. 2 Briefly, there are several indicators that the world is warming, including increases in atmospheric water vapor, increases in oceanic and troposphere temperatures, a cooling stratosphere, rising sea levels, decreases in sea ice and glaciers, and others.3 Furthermore, current trends show the greatest effects of climate change near the poles, particularly in the Arctic.2 There are several observed changes resulting from current climate change trends.2 Changes in the frost-free season have been observed as seasons have lengthened, influencing productivity of plant growth as well as types of plants growing (both beneficial and undesirable).2 Precipitation patterns have changed, with some areas experiencing increases and flooding as others have had decreases in precipitation and droughts. Moreover, incidence of heavier downpours and extreme precipitation has increased in the last 5 decades.4 Amongst the most notable effects are the frequency and intensity of extreme weather events. For instance, heat waves with record high temperatures have been occurring globally.3 Intense hurricanes, tornados, extreme winds, and other storms have been occurring more frequently and lasting longer in the last few decades, and are projected to worsen with increasing temperatures.3 Observed changes however are not limited to land, with greater than 90% of the energy stored and a quarter of atmospheric CO2 being accumulated by oceans, leading to acidification.5 Thus, globally the largest warming is noted near the oceanic surface, the upper 75 meters to be exact.5
Roots of Climate Change
A sizeable amount of evidence indicates that climate change and the Earth’s warming is primarily due to human influences. Emissions in anthropogenic greenhouse gases, largely influenced by population and economic growth, have increased since the Pre-Industrial Era.6 Primary influences include the emission of heat trapping gases such as Methane, Carbon Dioxide, and Nitrous Oxide, which have led to greater energy uptake by the Earth’s climate system.7 Encompassing 81% of all emissions, Carbon Dioxide results from fossil fuels, waste processes, chemical reactions, wood products, etc.8 Methane emissions from coal production, agricultural and livestock practices, and Nitrous Oxide emissions from industrial and agricultural activities comprise 11% and 6% of total emissions respectively.8 Potent, Synthetic Fluorinated gases from industrial processes comprise the remaining 3% of all greenhouse gas emissions.8 Total emissions (CO2 equivalents) in 2014 were approximately 6,870 million tons, with CO2 concentrations exceeding 400 parts per million globally in March 2017, the highest in history.9 Additionally, a 90% increase in CO2 emissions has been observed since 1970.8 The effects of individual gases depend on various factors including atmospheric concentration, the length of time the gas remains in the atmosphere, and their individual impacts on global temperature (potency).7 Yet, with knowledge of heat trapping gases and their effects, some may argue that climate change is not driven by human activities. To illustrate just that, experts have constructed models of corals, ice cores, tree rings, etc. that show the unusual nature of changes in surface temperatures.2 Furthermore, climate models that simulate climate change over the past 100 years have been created to separate human factors from natural ones. Such models indicate that with the removal of human factors, natural factors cannot account for the observed warming.2 In fact, volcanoes, solar forcing, and other natural drivers would have resulted in a slight cooling within the past 50 years.2Natural causes of climate change would have led to equal effects on the Earth’s atmospheres. More precise “fingerprint” studies have also been conducted which are able to ascribe individual causes to observed changes.2
Impacts of Climate Change
Climate change impacts various sectors including human health, forests, ecosystems, energy, water, agriculture, transportation, land use, biochemical cycles, and others. The effects of climate change on human health are dependent upon location, resources, age, socioeconomic status, etc.10 Promotion of allergens through longer frost-free seasons is one impact of climate change on human health. As air temperatures increase, flowering patterns shift and pollination rises resulting in increased plant based allergens and thus greater allergen sensitization and asthmatic episodes.10 Furthermore, increased ground level ozone which is influenced by heat (among other factors) is linked to reduced lung function and other respiratory conditions like asthma.10 Since 2010, the prevalence of asthma in the United States had increased to 8.4% (from 7.35% in 2001).10 Moreover, heat stress and other extreme weather events cause increased injury and disease incidence in populations. Vector-borne disease distribution is also influenced by variability in climate and is often increased in warmer and wetter regions.11 Such diseases include Plague, Dengue Fever, Lyme Disease, Tularemia, and others whose transmission is sensitive to climate changes.11 In example, over 2,000 cases of West Nile Virus were reported in the U.S. as of January 2017.11 Similarly, transmission of water-borne diarrheal diseases such as salmonellosis is influenced by precipitation, water and air temperatures, and variation in climate and are more common at higher temperatures.12 As climate changes, the hydrologic cycle, the form, amount, natural variability, and timing of water and precipitation are altered. From 1895 to 2011, annual precipitation rates have increased by 2 inches, while some areas have witnessed decreased precipitation.4 These changes have direct effects on marine life, water quality (and water-borne diseases), agriculture, and other sectors.4 Such influences on water have had direct effects on sea-levels with an estimated 0.34 meter rise in sea-level by 2100 at the current rate +0.3mm/year.13 It is predicted that rising sea-levels may displace over 100 million individuals by 2080.13,16 Management of water to alleviate the related problems involves greater efficiency around homes and with irrigation, recycling when possible, and improvement of building infrastructure to endure flooding and other water related disasters. Additionally, climate change has a direct effect on agriculture and food security.14 With more frequent hotter days or heat waves, drought frequency increases resulting in drier soil, water loss, and reduced crop yields.14 Similarly, increased precipitation may also have negative impacts on crop yield. For instance, soybean and corn yields have diminished by 6% in areas with 30 C or hotter temperatures.14 Simply mitigating the problem by increasing water use is not plausible, especially in poorer, third world countries. To counteract this issue, farming advancements are required. According to Bernhard Schauberger, crop yields will decrease by 20% by 2100 if emissions are not aggressively reduced.17 Furthermore, these reduced yields result in increased malnutrition and food insecurity.15 This can be directly related to extreme weather events as well as gradual temperature increases.
Future Response Strategies
The future of the global climate is largely dependent upon heat-trapping gas emissions and the regulations set forth. It is a global issue and there are many national and international regulatory agencies committed to eliminating the problem. The leading international expert on climate change is the Intergovernmental Panel on Climate Change (IPCC) created by the United Nations Environmental Programme and the World Meteorological Association. Other organizations committed to alleviating the climate change problem include the U.S. Environmental Protection Agency, USAIDS Global Climate Change Program, United Nations Framework Convention on Climate Change, the Center for International Climate Change and Environmental Research (CICERO), and others. The IPCC’s current assessment predicts that temperatures will rise by another 0.5 to 8.6 F by the end of the century.1 While predictions and their accuracy are based on several factors that influence climate change, the IPCC has Representative Concentration Pathways (RCP 2.6 being most aggressive) that confidently forecast future climate change.3 The magnitude of the consequence of climate change is determined by climate feedbacks that augment or diminish the effects of human influences, as well as the existence of irreversible tipping points.2 For instance, the extreme loss of Artic Sea Ice may result in a permanent ice-less state.2 Response strategies for climate change involve both mitigation and adaptation. Mitigation involves societal behavior changes regarding future emission choices. Foremost are future greenhouse gas emissions. Even if all greenhouse emissions were halted, temperatures would still increase by 0.5 F in the next century.2 A current emissions reductions scenario would assume emission reductions by 70% by 2050 and overall negative emissions by the end of the century to limit temperature increases to 3.6 F.3 This sample reductions model would require energy sources in 2070 to be 45% fossil fuels (with carbon capture), 20% fossil fuels (no carbon capture) and the remaining 35% of energy to be renewable or nuclear.3 Even with such emissions reductions, overall CO2 atmospheric concentrations would not be reduced, but rather limited since the current removal rate for CO2 in the atmosphere is only half of the emission rate.2 Furthermore, in the next 25 years, annual CO2 emissions would need to peak at 44 billion tons/year and then decrease to meet aggressive reductions models.3 Continued emissions at the current rate would easily exceed this peak by the end of the decade. Thus, mitigation strategies alone are not sufficient and reactive and proactive adaptation strategies must be put into effect to plan for and adapt to unavoidable consequences. For instance, a combination of national strategies and community preparation must be implemented to deal with consequences of drier conditions, heat stress, floods, rising sea levels, crop yields changes, and other extreme events.2 While some, like EPA Chief Scott Pruitt, may claim that climate change is not driven by human activity, there is an excessive evidence to indicate otherwise. It is evident that climate change is an important issue that requires individual and global interventions to fully and appropriately addressed, and emission reductions are an important step to take.