Thousands of record-breaking weather events worldwide bolster long-term trends of enhancing warmth sways, intense precipitation, droughts and wildfires. A combination of observed trends, theoretical understanding of the climate system, and numerical modeling demonstrates that global heating is enhancing the risk of these types of events today. Debates about whether single events are “caused” by climate switch are illogical, but individual events suggest significant lessons about society’s vulnerabilities to climate switch. Reducing the future risk of extreme weather requires reducing greenhouse gas emissions and adapting to switches that are already unavoidable.
Typically, climate switch is described in terms of average switches in temperature or precipitation, but most of the social and economic costs associated with climate switch will result from shifts in the frequency and severity of extreme events. 1 This fact is illustrated by a large number of costly weather disasters in 2010, which tied 2005 as the warmest year globally since 1880. Two Incidentally, both years were noted for exceptionally bruising weather events, such as Hurricane Katrina in 2005 and the deadly Russian fever wave in 2010. Other remarkable events of 2010 include Pakistan’s fattest flood, Canada’s warmest year, and Southwest Australia’s driest year. 2011 continued in similar form, with “biblical” flooding in Australia, the 2nd best summer in U.S. history, devastating drought and wildfires in Texas, Fresh Mexico and Arizona as well as historic flooding in North Dakota, the Lower Mississippi and in the Northeast. Trio
Munich Re, the world’s largest reinsurance company, has compiled global disaster for 1980-2010. In its analysis, 2010 had the second-largest (after 2007) number of recorded natural disasters and the fifth-greatest economic losses. Four Albeit there were far more deaths from geological disasters—almost entirely from the Haiti earthquake—more than 90 percent of all disasters and 65 percent of associated economic damages were weather and climate related (i.e. high winds, flooding, strong snowfall, fever sways, droughts, wildfires). In all, 874 weather and climate-related disasters resulted in 68,000 deaths and $99 billion in damages worldwide in 2010.
The fact that 2010 was one of the warmest years on record as well as one of the most disastrous, begs the question: Is global heating causing more extreme weather? The brief and elementary response is yes, at least for warmth flaps and powerful precipitation. Five But much of the public discussion of this relationship obscures the link behind a misplaced concentrate on causation of individual weather events. The questions we ask of science are critical: When we ask whether climate switch “caused” a particular event, we pose a fundamentally unanswerable question (see Box 1 ). This fallacy assures that we will often fail to draw connections inbetween individual weather events and climate switch, leading us to disregard the real risks of more extreme weather due to global heating.
Climate switch is defined by switches in mean climate conditions—that is, the average of hundreds or thousands events over the span of decades. Over the past 30 years, for example, any single weather event could be omitted or added to the record without altering the long-term trend in weather extremes and the statistical relationship inbetween that trend and the rise in global temperatures. Hence, it is illogical to debate the direct climatological link inbetween a single event and the long-term rise in the global average surface temperature.
Nonetheless, individual weather events suggest significant lessons about social and economic vulnerabilities to climate switch. Dismissing an individual event as happenstance because scientists did not link it individually to climate switch fosters a unsafely passive attitude toward rising climate risk. The uncertainty about future weather conditions and the illogic of attributing single events to global heating need not stand in the way of activity to manage the rising risks associated with extreme weather. Indeed, such uncertainty is why risk managers exist – insurance companies, for example – and risk management is the correct framework for examining the link inbetween global climate switch and extreme weather.
An effective risk management framework accommodates uncertainty, takes advantage of learning opportunities to update understanding of risk, and probes today’s uncommon extreme events for useful information about how we should react to rising risk. Risk management eschews futile attempts to forecast individual chaotic events and concentrates on establishing long-term risk certainty; that is, an understanding of what types of risks are enhancing and what can be done to minimize future damages. An understanding of the meaning of risk and how it relates to switches in the climate system is crucial to assessing vulnerability and planning for a future characterized by rising risk.
BOX 1: Why can’t scientists say whether climate switch “caused” a given weather event?
Climate is the average of many weather events over of a span of years. By definition, therefore, an isolated event lacks useful information about climate trends. Consider a hypothetical example: Prior to any switch in the climate, there was one category Five hurricane per year, but after the climate heated for some decades, there were two category Five hurricanes per year. In a given year, which of the two hurricanes was caused by climate switch? Since the two events are indistinguishable, this question is nonsense. It is not the occurrence of either of the two events that matters. The two events together – or more accurately, the average of two events per year – define the switch in the climate.
Latest Extreme Weather
Since 2010 tied with 2005 as the warmest year on record globally, it should come as no surprise that Nineteen countries set fresh national high-temperature records; this is the largest number of national high temperature records in a single year, besting 2007 by two. 6 One of the countries was Pakistan, which registered “the greatest reliably measured temperature ever recorded on the continent of Asia” (128.Three °F on May 26 in Mohenjo-daro). 7 Strikingly, no fresh national record low-temperatures occurred in 2010. 8 Several historic warmth flaps occurred across the globe, as well. Unprecedented summer warmth in western Russia caused wildfires and demolished one-third of Russia’s wheat crop; the combination of extreme fever, smog, and smoke killed 56,000 people. 9 In China, extreme warmth and the worst drought in 100 years struck Yunan province, causing crop failures and setting the stage for further devastation by locust swarms. Ten In the United States, the summer of 2010 featured record cracking warmth on the east coast with temperatures reaching 106 degrees as far north as Maryland. 11 Records also were set for energy request and the size of the area affected by extreme warmth. 12 Even in California where the average temperatures were below normal, Los Angeles set its all-time high temperature record of 113 degrees on September 27.
Global precipitation was also far above normal, with 2010 ranking as the moistest year since 1900. 13 Many areas received record intense rainfall and flooding. Westward shifts of the monsoon dropped 12 inches of rain across broad areas of Pakistan, flooding the Indus Sea valley, displacing millions of people and destabilizing an already precariously balanced nation. 14 Rio de Janeiro received the most intense rainfall in 30 years—almost 12 inches in 24 hours, causing almost 300 mudslides and killing at least 900 people. 15
Developed countries also suffered debilitating downpours. On the high-heeled shoes of Queensland, Australia’s moistest spring since 1900, December rainfall broke records in 107 locations. 16 Widespread flooding trimmed an estimated $30 billion off Australia’s GDP. 17 The United States experienced several record cracking torrential downpours. In Tennessee, an estimated 1,000-year flooding event Legitimate brought more than a foot of rain in two days, resulting in record flooding and over two billion dollars in damages in Nashville alone, equivalent to a utter year of economic output for that city. In Arkansas, an unprecedented 7 inches of rain fell in a few hours, causing flash flooding as rivers swelled up to 20 feet. Nineteen Wisconsin had its moistest summer on record, which is remarkable given the series of historic floods that have impacted the upper Midwest over the last two decades.
In 2011, there have already been three separate historic floods in the United States, the driest 12 months ever recorded in Texas, and a record violating tornado outbreak (see Box Two ). 20 Damages from Hurricane Irene, much of which is flood related, are estimated to be inbetween $7 and $Ten billion, making it one of the top ten most bruising hurricanes ever to hit the US. 21
BOX Two: What about climate switch and tornadoes?
Scientists are uncertain if tornadoes will become stronger or more frequent, but with enlargened temperatures switching the weather in unexpected ways, the risk is real that tornado outbreaks will become more bruising in the future. The lack of certainty in the state of the science does not equate with a lack of risk, since risk is based on possibility. The lack of scientific consensus is a risk factor itself, and we must prepare for a future that could possibly include enlargened tornado harm.
The historic weather extremes of 2010 and 2011 fit into a larger narrative of bruising extreme weather events in latest decades. Latest fever flaps in Russia and the United States have evoked memories of the 1995 fever wave that killed hundreds of Chicagoans, and the 2003 European fever wave that killed at least 35,000 people. 22 In the United States, the number of storms costing more than $100 million has enlargened dramatically since 1990. Albeit the 2010 flooding in the American Midwest was very hurting, it was not on the scale of the 1993 and 2008 events, each costing billions of dollars and of such ferocity that they should be expected to occur only once in 300 years. 23 Other unprecedented disasters include the 2008 California wildfires that burned over a million acres, 24 and the decade-long Southwest drought, which proceeds in spite of an uncharacteristically raw winter. 25 Mumbai, India, recorded its highest ever daily rainfall with a deluge of 39 inches that flooded the city in July of 2005. 26 This neared the Indian daily record set the year before when 46 inches fell in Aminidivi, which more than doubled 30-year-old record of 22.6 inches. 27 Torrential downpours continued for the next week, killing hundreds of people and displacing as many as 1 million. 28
Taken in aggregate, this narrative of extreme events over latest decades provides a few snapshots of a larger statistical trend toward more frequent and intense extreme weather events. Rising frequency of intense downpours is an expected consequence of a heating climate, and this trend has been observed. Some areas will see more droughts as overall rainfall decreases and other areas will practice intense precipitation more frequently. Still other regions may not practice a switch in total rainfall amounts but might see rain come in rarer, more intense bursts, potentially leading to flash floods punctuating periods of chronic drought. Therefore, observed trends in warmth, mighty precipitation, and drought in different places are consistent with global heating. 29
Over the past 50 years, total rainfall has enhanced by 7 percent globally, much of which is due to enlargened frequency of powerful downpours. In the United States, the amount of precipitation falling in the most intense 1 percent of rain events has enlargened by almost 20 percent overall, while the frequency of light and moderate events has been sustained or decreasing (Fig. 1 ). 30 Meantime, fever sways have become more humid, thereby enhancing biological fever stress, and are increasingly characterized by utterly high nighttime temperatures, which are responsible for most heat-related deaths. 31 In the western United States, drought is more frequent and more persistent, while the Midwest practices less frequent drought but more frequent strong precipitation. 32
Record daytime and nighttime high temperatures have been enhancing on a global scale. 33 In the United States today, a record high temperature is twice as likely to be cracked as a record low, and nighttime temperature records demonstrate a strong upward trend (Fig. Two ). By contrast, record highs and lows were about identically likely in the 1950s (Fig. Trio ). 34 This trend shows that the risk of fever sways is enhancing over time, consistent with the results of global climate models that are compelled by rising atmospheric greenhouse gas concentrations. 35 Indeed, the observed fever wave intensities in the early 21st century already exceed the worst-case projections of climate models. 36 Moreover, the distribution of observed temperatures is broader than the temperature range produced by climate models, suggesting that models may underestimate the rising risk extreme warmth as heating proceeds.
Figure 1: Increases in the Number of Days with Very Intense Precipitation (1958 to 2007)
Percentage increase in strenuous downpours in the regions of the United States since the late 1950s. The map shows the percentage increases in the average number of days with very strong precipitation (defined as the most powerful 1 percent of all events) from 1958 to 2007 for each region. There are clear trends toward more days with very strenuous precipitation for the nation as a entire, and particularly in the Northeast and Midwest.
Climate Switch and the Rising Risk of Extreme Weather
When averaged together, switching climate extremes can be traced to rising global temperatures, increases in the amount of water vapor in the atmosphere, and switches in atmospheric circulation. Warmer temperatures directly influence fever swings and increase the moisture available in the atmosphere to supply extreme precipitation events. Expanding sub-tropical deserts full salute out from the equator are creating larger areas of burying, dry air, thus expanding the area of land that is subject to drought. 37 The expansion of this sub-tropical circulation pattern also is enhancing warmth transport from the tropics to the Arctic and pushing mid-latitude storm tracks, along with their rainfall, to higher latitudes.
As discussed above, no particular short-term event can be conclusively attributed to climate switch. The historical record provides slew of examples of extreme events occurring in the distant past and such events obviously occur without requiring a switch in the climate. What matters is that there is a statistical record of these events occurring with enlargening frequency and/or force over time, that this trend is consistent with expectations from global heating, and that our understanding of climate physics indicates that this trend should proceed into the future as the world proceeds to warm. Hence, a probability-based risk management framework is the correct way to consider the link inbetween climate switch and extreme weather.
It is also significant to disentangle natural cycles from climate switch, both of which are risk factors for extreme weather. Consider an analogy: An unhealthy diet, smoking, and lack of exercise are all risk factors for heart disease, and not one of these factors can or should be singled out as the cause of a particular heart attack. Similarly, a particular weather event is not directly caused by a single risk factor but has a higher probability of occurrence depending on the presence of various risk factors. The influence on risk from different sources of climate variability is additive, so global heating presents a fresh risk factor added on top of the natural ones that have always been with us. Over time, natural cycles will come and go, but global heating will proceed in one direction such that its contribution to risk will reliably increase over time. Global heating has simply added an extra and ever rising risk factor into an already risky system (see Box Trio ).
BOX Trio: The 2011 Texas drought: A case explore in numerous risk factors
Over the past year, Texas has experienced its most intense single-year drought in recorded history. Texas State Climatologist John Nielsen-Gammon estimated the three sources of climate variability – two natural cycles plus global heating – that contributed to the drought’s unprecedented force:
- La Nina, 79%
- Atlantic Multidecadal Oscilation, 4%
- Global Heating, 17%
Albeit information about uncertainty is lacking in this analysis, it clearly identifies global heating as one of the risk factors.
Extreme events are often described by their expected frequency of recurrence. A “25-year event” has a statistical expectation of occurring once in 25 years, on average. It may occur more than once in any 25 year span or not at all for a utter century, but over many centuries it is expected to occur on average once every 25 years. Events with a longer recurrence time tend to be more severe, so that a 100-year flood is a more dreaded event than a 25-year flood. A 500-year flood would be even more bruising, but it is considered to be so uncommon that people generally do not worry about events of such a magnitude. The problem with climate switch, however, is that what used to be a 500-year event may become a 100-year or 10-year event, so that most people will practice such events within their lifetimes.
Risk cannot be thought of in a discontinuous way, with singular events having predictive power about specific future events. Risk is the accumulation of all future possibilities weighted by their probabilities of occurrence. Therefore, an increase in either disaster frequency or severity increases the risk. Events can be ordered on a future timeline and ranked by expectations about their frequency, but this only describes what we expect to happen on average over a long period of time; it does not predict individual events. Consequently, impacts are uncertain in the brief term, but the risk of impacts will rise in a predictable style. Risk therefore tells us what future climate conditions we should plan for in order to minimize the expected costs of weather-related disasters over the lifetime of long-lived investments, such as houses, levees, pipelines, and emergency management infrastructure.
Risk management is used extensively almost anywhere decision-makers are faced with incomplete information or unpredictable outcomes that may have negative impacts. Classic examples include the military, financial services, the insurance industry, and uncountable deeds taken by ordinary people every day. Homeowners insurance, bicycle helmets, and car seatbelts are risk-management devices that billions of people employ daily, even tho’ most people will never need them.
Figure Two: Contiguous U.S. Extremes in Minimum Temperature (Step Two) Summer (June-August) 1910-2011
Switches in land area (as percent of total) in the contiguous 48 U.S. states experiencing extreme nightly low temperatures during summer. Extreme is defined as temperatures falling in the upper (crimson bars) or lower (blue bars) 10th percentile of the local period of record. Green lines represent decade-long averages. The area of land experiencing unusually cold temperatures has decreased over the past century, while the area of land experiencing unusually hot temperatures (crimson bars) reached record levels during the past decade. During the Dust Cup period of the 1930s, far less land area experienced unusually hot temperatures.
Source: NOAA NCDC Climate Extremes Index (2011) (Ref. 38 ).
Figure Three: Ratios of record highs to record lows for successive decades in the United States
A non-changing climate would have approximately equal numbers of record highs and lows, as observed in the 1950s-1980s. The last decade (2000s) had twice as many record highs as it did record lows.
Source: Meehl et al. 2009 (Ref 33 ); figure ©UCAR, graphic by Mike Shibao
Understanding Climate Risk
The extreme events cataloged above and the trends they reflect provide a proxy for the types of events society will face with greater risk in the future. With a clear record of trends and reasonable projections for the future, the level of risk can be assessed and ready for. Risk can be thought of as a continuous range of possibilities, each with a different likelihood of occurring; extreme outcomes reside on the low-probability tails of the range or distribution. For example, climate switch is widening the probability distribution for temperature extremes and shifting the mean and the low-probability tails toward more frequent and intense fever events (Fig. Four ).
Figure Four: Increase in Mean Temperature and Variance.
Conceptual representation of the shift in the probability distribution for average and extreme temperatures as a result of global heating. The frequency of extreme high temperatures increases non-linearly, while extreme lows demonstrate a more muted response.
Source: Adapted from IPCC (2001) (Ref. 39 ).
The rising risk of extreme events has much in common with playing with loaded dice, where the dice are weighted to roll high numbers more frequently. Moreover, one of the dice has numbers from two to seven instead of one to six. It is therefore possible to roll a 13 (i.e. the maximum possible temperature is higher than before) and would be more likely (because the dice are loaded) than rolling a 12 with two normal dice. The probability distribution of the loaded dice compared to normal dice is translated into switching climate risk in Figure Four. With normal dice, one can expect to roll snake eyes (cold extremes) about identically as often as dual sixes (hot extremes). But with climate switch, the dice are loaded so that cold extremes (as defined in the previous climate) are a bit less likely than they used to be and hot extremes are sexier and more likely than before.
The fresh risk profile presents a nonlinear increase in the number of extremes on one tail (i.e. warmth sways). In light of latest cold winters in the United States and Europe, it is significant to recognize that this fresh curve does not dispense with cold extremes, as the widening of the distribution (i.e. increase in variability) partially offsets the shift toward warmer events. Cold extremes become less frequent but do not vanish (Fig. Four). Moreover, like strenuous downpours, mighty snowfall is also consistent with global heating (see Box Four ).
Under this fresh risk profile, the probability of record warmth increases dramatically. The deadly 2003 European fever wave offers an example of a real world event that conforms to this fresh expectation. An event of that magnitude has a very puny probability under the unchanged climate regime but has a much higher probability under a fresh climate profile that is both sexier and more variable (Fig. Five ). Since this event actually happened, we know that an event of that energy is possible, and model projections tell us that the risk of such an event should be expected to rise dramatically in the coming decades due to global heating. Indeed, a 50 percent increase in variance alone, without even shifting the average temperature, could make the 2003 warmth wave a 60-year event rather than a 500-year event under the old regime. 40 Other research has indicated that the risk of a 2003-type warmth wave in Europe is already twice as large because of heating over latest decades. With continued heating, the frequency of such an event could rise to numerous occurrences per decade by the middle of this century. 41
Figure Five: Warmth of the 2003 European fever wave relative to historical summer temperatures (1961-1990) and future (2071-2100) summer temperatures as projected by a climate model
Historically 2003 is exceptionally warm but in the future script it has become relatively common.
Source: Schar et al. 2004 (Ref. 38) as redrawn by Barton et al. 2010 (Ref. 42 ).
Hot extremes are not the only sort of weather event to have enhanced beyond expectations. Observed increases in extreme hourly precipitation are beyond projections, even while daily precipitation switches remain within expectations. This indicates that the scaling of precipitation with increases in atmospheric moisture is not consistent inbetween brief bursts and total amounts over longer periods. In the Netherlands, a probe shows that one-hour precipitation extremes have enlargened at twice the rate with rising temperatures as expected when temperatures exceed 12°C. 43 This is another example of the type of rapid increase in extreme events that is possible when the risk distribution is not only shifted but also exhibits enlargened variance.
BOX Four: Can global heating cause intense snow?
In December 2009 and February 2010, several American East Coast cities experienced back-to-back record-breaking snowfalls. These events were popularly dubbed “Snowmageddon” and “Snowpocalypse.” Such events are consistent with the effects of global heating, which is expected to cause more powerful precipitation because of a greater amount of water vapor in the atmosphere. Freezing temperatures are normal during the winter for cities like Washington, D.C. Philadelphia, and Fresh York. Storms called Nor’easters are also normal occurrences. As global heating evaporates more water from the Gulf of Mexico and the Atlantic Ocean, the amount of atmospheric moisture available to fuel these storms has been enhancing, thus elevating the risk of “apocalyptic” snowstorms.
Attributing Risk and Assessing Vulnerability
It should be clear that while one cannot attribute a particular weather event to climate switch, it is possible to attribute and project switches in risk of some categories of extreme weather. In order to have confidence in any climate-related risk assessment, the connection inbetween climate switch and a particular type of weather event needs to be established by numerous lines of evidence. This connection relies on three supporting avenues of evidence: theory, modeling and observation, which can be viewed as the gams of a stool (Fig. 6 ). Very first, scientists must understand the physical basis of why a type of weather event ought to react to climate switch. To assess whether such a response has already begun, observational data should showcase an increase in frequency, duration, or power that is commensurate with the physical understanding. Ultimately, computational models coerced by elevated greenhouse gas concentrations should display an increase in risk that is consistent with theory and observation.
Figure 6: Three-legged stool paradigm for assessing the switching risk of extreme weather due to global heating
Physical understanding (theory) should provide a reason to expect a switch in risk. Observations are needed to confirm that a switch is taking place and computational modeling can be used to determine whether the observations reconcile with the theory and, if so, to project future switches in risk.
There is supporting evidence in all three areas (theory, modeling, and observation) pointing to a global-warming induced increase in risk for four significant categories of weather-related extreme events: extreme warmth, intense downpours, drought and drought-associated wildfires. For some other types of weather events, there is not sufficient evidence to conclude that global heating has enlargened risk. For example, evidence relating hurricane risk to climate switch is “two-legged”: There is a physical basis for expecting hurricanes to have stronger winds and produce more rainfall due to global heating, and models with enhanced greenhouse gas levels showcase an increase in the number of such storms. With two gams of the stool, hurricanes are a type of event that we should consider a potential future threat for enlargened risk, but more research is needed to confirm. However, observational evidence is insufficient to confirm that such a response has already begun. For tornadoes, the evidence is “zero-legged,” meaning that neither theory, modeling, nor observation suggest any indication of how tornado risk has switched or might switch in the future due to global heating, albeit that does not mean there is no risk (see Box Two).
In addition to aggregate trend analysis, planners and policymakers can and do use individual extreme weather events as laboratories for assessing social and economic vulnerabilities and crafting adequate deeds to minimize the suffering and costs expected from similar events in the future. For example, in 1995 a prolonged fever wave killed hundreds in Chicago, after which the city took effective steps to prepare for future fever swings. 44 Prior to the 2003 European fever wave, the possibility that such a deadly fever wave could strike Europe had not been considered. Now that European society is aware of this possibility, preparations have been made to decrease future suffering and economic harm. Similarly, Hurricane Katrina demonstrated that a major American city can be paralyzed for weeks, without effective emergency response, communications, security, sanitation, or health care. Other latest examples of flooding and extreme rainfall should provide lessons on where flood control and emergency response systems are most needed and how much the investments in prep are worth. Additionally, extreme events represent data points that can improve trends and estimates of future risk, as it is critically significant to update trends for estimating existing risk as well as future risk.
Responding to Rising Risk
Both adapting to unavoidable climate switch and mitigating future greenhouse gas emissions are required to manage the risks of extreme weather in a warmer climate. Since limiting the amount of COTwo in the atmosphere boundaries the magnitude of climate switch in general, reducing COTwo emissions is effective at preventing both linear increases in risks and the more difficult to predict, nonlinear switches in extremes. Due to this property, mitigation activity can be thought of as a benefit multiplier, as linear decreases in emissions can result in nonlinear decreases in extreme risk. Conversely, since climate switch is already underway, some impacts are unavoidable and society must adapt to them. In order to be effective, adaptation deeds must be commensurate with the magnitude of the risk. Nonlinear increases in risk associated with weather extremes require adaptation deeds beyond what would be expected by looking at switches in average climate conditions. Moreover, many adaptation options are likely to be infeasible if the climate switches too much; adequate mitigation is therefore required to facilitate successful adaptation.
Science is not a crystal ball, but it offers powerful devices for evaluating the risks of climate switch. Scientists can investigate whether the risk of certain types of events is rising by examining latest trends, and also whether the risks are likely to rise in the future using projections from climate models. When these two indicators converge, we should look to reduce vulnerability to such events. Indeed, a growing assets of research is using climate models as a mechanism for investigating future increases in risk. Models cannot predict specific events but for some types of extremes they can indicate how risk profiles are likely to switch in the future. This treatment is particularly powerful when benchmarked against actual events that society agrees should be guarded against.
In 2000, the United Kingdom experienced devastating autumn floods associated with meteorological conditions that are realistically mimicked in climate models. In a climate model, the risk of severe autumn flooding enlargened by 20 to 90 percent under present-day greenhouse gas concentrations compared to preindustrial concentrations. 45 Conversely, modeling simulations of the deadly 2010 Russian fever wave found no evidence that climate switch has so far enlargened the risk of such an event but did find that continued heating is very likely to produce frequent warmth swings of a similar magnitude later this century. 46 Hence, regardless of the cause of that particular warmth wave, the risk of similar events in the future can be expected to rise with continued heating of the global climate. Because the event was so deadly and economically harmful, the rising risk of similar events should prompt serious consideration of suitable deeds to limit and adapt to this risk.
Given the uncertainties and risks, it does not make sense to concentrate on whether current events are supercharged by climate switch. It does make sense, however, to take lessons from them about our current vulnerabilities and the risks inherent in unabated greenhouse gas emissions that drive extreme weather risks ever higher as time passes. Climate science can provide risk-based information that decision makers can use to understand how the risk is switching so that they can prioritize and value investments in prevention and adaptation.
Other C2ES Resources:
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11 National Climatic Data Center. Top Ten US Weather/Climate Events of 2011. Retrieved May Nineteen, 2011, from http://1.usa.gov/lGpdnE .
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25 Carlton, J. (2011, March 31). Raw Winter Can’t Slake West’s Thirst. Retrieved May Nineteen, 2011, from Wall Street Journal: http://on.wsj.com/gmPD3t .
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