Climate Change Test 1
What evidence do we have that climate change that has occurred since the industrial revolution, and especially in the last 60 years, is due primarily to anthropogenic increases in the greenhouse gases?
-In 1850, the ppm for CO2 was 270 ppm which was -14 C and now, it is 410 ppm which is -15 C . But in the last century, the burning of fossil fuels has rapidly driven atmospheric CO2 levels to new heights, overriding the natural cycle. - The concentration for methane has more than doubled since preindustrial times rising to 1.8 ppm - due to agriculture and fossil fuel use - Nitrous oxide has risen to a new high also reaching over 0.3 ppm -Humans cause a lot of pollution by producing much CO2 and other greenhouse gases . - CO2 is formed by burning fossil fuels . -anthropogenic methane is produced from wetlands ,livestock and farming & leakage from the oil and gas industry, belching by cattle . POSITIVE FEEDBACK WITH METHANE AND WARMING: permafrost melting and decomposing & methane clathrate melting in ocean . -nitrous oxide has increased by 16% since the start of industrial age . It's produced by fertilizer -CFCs - refrigerants and aerosols: led to destruction of ozone layer in stratosphere over Antarctica, 5% loss of ozone column over mid-latitudes, the MONTREAL PROTOCOl outlawed CFCs which took 3 years to implement, powerful greenhouse gas that is 5,000 to 10,000 times as effective as CO2, THEY WERE REPLACED BY HCFCs which break down faster and affect the ozone much less
How has the climate changed in the last 11,000 years, last 100 years, and last 150 years? Be sure to mention cooling since the thermal optimum at the end of the last ice age, the Medieval Warm Period, the Little Ice Age, and what has happened in the last 150 years.
-Medieval Warm Period: A period around 1000 AD that lasted almost 350 years . Relatively warm conditions are said to have prevailed in various parts of the world, predominately through Northern Hemisphere from Greenland westward through Europe and Asia. It was started by a short warming period due to less volcanic activity and more solar radiation. It led to stable warming due to two factors: a strong positive North Atlantic Oscillation (NAO) & a change to a La Nina dominated Pacific. -The Little Ice Age: 13-19th century when average temps were cooler than they are now. Sunspot activity causes short term warming when it increases and there are periods of time when longer term changes in sunspot activity occur and one such period was the Little Ice Age . Sunspots are storms on the sun's surface that are marked by intense magnetic activity. -Coral bleaching has been occurring: when water is too warm, corals will expel their algae causing the coral to lose their color . when they bleach, they are not dead , but they're subject to mortality . 25% of marine life depends on the habitat created by coral reefs . -Butterfly emergence is shifting earlier by 1.6 days per decade over the last 65 years in Melbourne -hurricanes are gaining more intensity because water is getting warmer - hurricanes pick up energy off of warm water -Milankovich Cycles- engineer who put forward hypotheses that explained the retreat and advance of the ice ages which were later confirmed. According to the Milankovich Cycles, the Earth's current warming is just a part of a series of cyclical events that take thousands of years to complete and cannot be prevented. The main point is the greater the difference in seasons, the warmer it will be . When summers are cool, ice accumulates . The first is eccentricity which is the path of the Earth's orbit around the sun is not a perfect circle, but an ellipse. The Earth's orbit undergoes a cyclical change from less eccentric to more eccentric and back. The second is axial tilt. The seasons are more intense at greater tilt. Lower tilt results in ice ages. The third is precession (wobble). This affects the intensity of seasons in different hemispheres. Right now ,seasons are more intense in southern hemisphere than in the northern.
What are proxy data, and how have they been used by climatologists to demonstrate that recent climate change is unlike any change in climate over the last 11,000 years?
-Proxy data are preserved physical characteristics of the environment that can stand in for direct measurements. --Paleoclimatologists gather proxy data from natural recorders of climate variability such as tree rings, ice cores, fossil pollen, ocean sediments, corals and historical data. -By analyzing records taken from these and other proxy sources, scientists can extend our understanding of climate far beyond the instrumental record.
Explain the basic theory of anthropogenic climate change .
-Sunlight penetrates the gas layer of the atmosphere which is partly reflected by into space by ice and land but also partly absorbed . Small particles in the air ensure that a percentage of the reflected radiation is sent back to Earth . Humans cause a lot of pollution by producing much CO2 and other greenhouse gases . - CO2 is formed by burning fossil fuels . -anthropogenic methane is produced from wetlands ,livestock and farming & leakage from the oil and gas industry. POSITIVE FEEDBACK WITH METHANE AND WARMING: permafrost melting and decomposing & methane clathrate melting in ocean . -nitrous oxide is produced by fertilizer -ozone: ozone is produced by car smog and in the upper atmosphere by jet planes which release nitrogen oxides
Two phenology studies used historical phenology observations of Thoreau and other naturalists to look at the impacts of climate change in the area of Walden Pond, near Concord, MA . What were the major findings of these studies?
-Thoreau spent decades carefully recording the natural history of plants -Botanists have resurveyed the Concord area 27% of species documented by Thoreau are lost from the area -36% are in threat of imminent extinction -this despite 60% of area being well protected major causes: habitat alteration(wetland loss, road and home construction) & climate change- mean temp increase of 2.4 C -in Thoreau's first data 1, "Ecology," he collected dates of first bloom for 500 plants -His data 2 showed average flowering shift of 7 days earlier -species evolutionary history is important to understanding community response to climate change -species that are declining in abundance are more closely related to one another than expected by chance -closely related species have similar flowering time and responses to change -phylogeny is not important in explaining the latitudinal range of a species -ability to track seasonal temp is crucial to persistence -SPECIES THAT ARE NOT FLOWERING EARLIER ARE DECLINING -species range was correlated with change in abundance- more northerly distributed species have decreased more southerly distributed species - previous studies have documented declines in the same groups -this is the first time that extinction risk is directly correlated with traits that are known to be affected by changes in climate (growing season)
What are some of the characteristics of the NE US that make it socioeconomically important? What are the chief climate hazards this region faces in the future?
-Washington Dc through Boston is one of the most developed environments in the world and home to one of the world's leading financial centers and the nation's capital . -The twelve NE states have more than 180,000 farms, with $17 billion in annual sales. -climate hazards: -heat waves, droughts (this will pose a growing challenge to the region's environmental, social, and economic systems & increase the vulnerability of the region's residents) -health risks from insect-borne diseases will increase -contamination of water -sea level rise, storm surge, heavy precipitation (one of the reasons sandy was so bad) THIS WILL put infrastructure at risk - ice storms, blizzards, severe cold in winter -hurricanes and other major storms in the Atlantic Ocean off the NE coast -if carbon emissions continue to increase, warming of 4.5 to 10 F is projected by the 2080s -on the contrary, if global emissions were reduced substantially, projected warming ranges from 3 to 6 F by the 2080s
What biomes are represented in each of the two regions of the US we have discussed so far (NE, MW)? What are the primary characteristics (vegetation, seasonality) of each of these biomes? Which of these biomes do you think are most threatened by climate change, and why do you think that? I will save the tundra, chaparral, desert, and tropical biomes for the second exam when we discuss the regions in which they occur .
-biome= major biogeographical regions with unique accumulations of flora and faunaThe -TAIGA: long, cold winter, short, warm summers, liquid water unavailable during winter months permafrost only in northern-most regions, vegetation= low diversity and productivity, dominated by conifers and birch, important as carbon sinks -major threats to taiga biodiversity: global climate change, commercial logging, mining , oil and gas drilling -TEMPERATE FORESTS: warm, moist summers, cold, sometimes snowy winters, precipitation occurs throughout the year, vegetation = generally dominated by deciduous trees , moderate tree diversity, diverse understory, moderate productivity -major threats to temperate deciduous forest biodiversity: urbanization, air pollution, logging, invasive species, fragmentation -GRASSLANDS: moderately dry, most precipitation occurs in summer, cold winters, warm-hot summers, seasonal drought, obviously dominated by grass, vegetation = controlled by fire, grazing, many grasslands used for agriculture -major threats to grassland biodiversity: conversion to irrigated agriculture, anthropogenic disturbance, grazing, invasive species
What caused the repeated ice ages over the last 2 million years, and what is the typical length of an ice age cycle?
...
There are seven major positive feedback mechanisms for accelerated global warming . List these seven feedbacks and give enough explanation for each so that I can see you understand how these work .
1. Water Vapor: Climate warms slightly from CO2 release . If no feedbacks occur, we just have the radiative forcing of additional CO2 . However, we know we have feedback from water vapor . Higher temperature leads to more evaporation from oceans and wet land surfaces . This water vapor will double the temperature increase. Also, clouds interfere with transfer of radiation in the atmosphere in two ways. Clouds reflect a certain proportion of solar radiation back to space (high albedo) reducing energy available to the system (cooling). Clouds also act as a blanket to thermal radiation from the earth's surface. Lastly, oceans play a major role in existing climate. Evaporation from oceans is a main source of atmospheric water vapor, which is the largest heat source for the atmosphere. 2. Warming Ocean Feedbacks: There is a decreased absorption of CO2 by oceans . Warmer water holds less CO2. As a result, more of our carbon pollution will stay in the atmosphere, causing global warming 3. Acidified Ocean Feedbacks: Some areas of the ocean are becoming acidified due to excess CO2 in the atmosphere- this could lead to the decrease in calcified organisms that can no longer produce calcium carbonate . 4. Warming and methane clathrates: methane clathrates are methane complexed in water ice . It is kept in the sediment by high pressure and cold temps. Methane in Siberia has been increasing which is possibly tied to melting clathrates. Thought to be responsible for the global warming that caused the End-Permian Mass extinction (95% of species went extinct) 55.8 million years ago. 5. Ice- albedo feedback: Ice has a very high albedo (reflects light back into space)- as it melts, it exposes land and water, both of which absorb more light and heat, reducing reflectivity (it then warms) 6. Permafrost and soil feedbacks: when permafrost melts, lakes disappear because organic matter in soil breaks down and methane and CO2 are released which, in turn, the greenhouse gases lead to more warming. 7. Forest Loss Feedbacks: Forest fires: rates of forest fires have greatly increased in the western US . The primary fear is that drought in the tropics could lead to fires that cause conversion of Amazon Rain Forest to Caatinga
The Heartland Institute, a tax-exempt educational institution, had plans to develop a K-12 global warming curriculum . What two key points did they want to emphasize that have been especially effective at "dissuading teachers from teaching science."
Heartland was planning to bring denial into the classroom, by developing a school curriculum "that shows that the topic of climate change is controversial and uncertain - two key points that are effective at dissuading teachers from teaching science". They rather teach the controversy rather than teaching the science . . They were also hoping to pursue funding from "corporations whose interests are threatened by climate policies" - presumably the fossil fuel industry
What is the HockeyStick Controversy, and what was the result of all of the investigations into this scientific study?
In the hockey stick controversy, the data and methods used in reconstructions of the temperature record of the past 1000 years have been disputed. Reconstructions have consistently shown that the rise in the instrumental temperature record of the past 150 years is not matched in earlier centuries, and the name "hockey stick graph" was coined for figures showing a long-term decline followed by an abrupt rise in temperatures.In 1998, Michael E. Mann, Raymond S. Bradley and Malcolm K. Hughes developed new statistical techniques to produce Mann, Bradley & Hughes 1998 (MBH98), the first eigenvector-based climate field reconstruction (CFR). This showed global patterns of annual surface temperature, and included a graph of average hemispheric temperatures back to 1400.[4] In Mann, Bradley & Hughes 1999 (MBH99) the methodology was extended back to 1000.[5][6] The term hockey stick was coined by the climatologist Jerry D. Mahlman, to describe the pattern this showed, envisaging a graph that is relatively flat to 1900 as forming an ice hockey stick's "shaft", followed by a sharp increase corresponding to the "blade" -Conclusions from MBH 1999 was that the 20th century is the warmest century in this millennium. Also, the mid to late 20th century is significantly higher than any previous warm period. AND both the past decade and pas year are likely the warmest for the northern hemisphere THIS MILLENNIUM . - Stephen McIntyre and Ross McKitrick questioned article on statistical grounds in 2003 paper in "Energy and Environment." "Energy and environment" is an industry publication and not a peer-reviewed scientific journal . - in 2005, congressman Joe Barton called for an inquiry into the hockey stick controversy and wrote a letter to Mann requesting he provide his data, including his source code, archives of all data from all of Mann's scientific publications, and much more - AAAs considered this request inappropriate but Mann complied giving everything -NAS and NRC did reports on this subject and both 2006 reports confirm MBH98 in terms of conclusions and integrity; they soften the conclusion regarding the "warmest temperatures in the last 1000 years." -MBH 1998 and 1999 had no serious errors and the papers stand -this was resurrected as the "climategate scandal"- emails of MBH and Phil Jones were hacked and leaked- all scientists (after investigations) were cleared of any wrong-doing
Looking at the predicted impacts of climate change in the Midwest, which two impacts do you think will be widely perceived as most terrible, and why? Give enough details about these impacts that someone unfamiliar with climate change would understand you concern.
The impact of maximum temp will be bad because if the max temp during the summer increases, a decrease in producing of both corn and soybeans will be experienced. with increased temps come heat waves. In July 2011, 132 million people across the US were under a heat alert and temps were over 100 F . Chicago heat waves killed 114 people in 1999 and 700 in 1995 . These dangers will keep going up . Also, extreme rainfall events and flooding have increased during the last century, and these trends are expected to continue, causing erosion, declining water quality, and negative impacts on transportation, agriculture, human health and infrastructure
What are some of the weather indicators and physical indicators that provide evidence that the climate has changed in recent years
weather: -global mean temp has increased by 1.0 C (1.8 F) since 1850 -hot days/ heat index increased -cold/ frost days decreased continental precipitation increased 5-10% over last century, but decreased in other areas -heavy precipitation events increased -drought increased -tropical cyclones increased in intensity physical: -global average sea level has risen steadily -arctic sea ice has thinned and is smaller -snow cover decreased by 10% according to satellite data -permafrost has thawed and degraded biological: -growing season lengthened 1-4 days per decade in the last 50 years -coral reefs are bleaching due to heat -plants flower earlier, birds migrate earlier
