cc impact implication_informative

Global Warming: Impact and Implications

EcoLogic Consultancy Copyright © 2009

EcoLogic Consultancy

Informative Note on Global warming: Impact and Implications 2

Content Introduction

Viewfromtheotherside

Probableimpactandimplications

Actnow–toolateortoosoon



Introduction Various human activities especially industrial ones add emissions to the atmosphere. Such gases/particles emitted have not been part of the atmosphere ever. ‘Climate change’ encompasses the wide variety of accompanying impacts on temperature, weather patterns and other natural systems. What is unique about current global climate change, relative to historical changes, is the causal role of human activity (also called anthropogenic forcing) and the current and projected dramatic changes in climate across the globe. Heat-trapping ‘greenhouse gases’ in the atmosphere (of which the two most important are water vapor and carbon dioxide, CO2) let through short-wave radiation from the sun but absorb the long-wave heat radiation coming back from the Earth’s surface and re-radiate it. These gases act like a blanket — and keep surface and lower atmosphere about 33° C warmer than it would be without them. Earth’s greenhouse blanket is a good balance between the extremes of our neighbours: Mars, without any greenhouse gases, is a frozen wasteland; whilst Venus remains trapped in a dense blanket of hot CO2. Various human activities including burning of fossil fuels, and long-term deforestation, humans have been increasing the concentration of CO2 and other greenhouse gases in the atmosphere since the industrial revolution began, thickening the greenhouse blanket. The enhanced concentration of greenhouse gases is believed to be responsible for raising the mean temperature of the earth’s surface above that occurring due to the natural greenhouse effect (Effect of greenhouse gases without human activities). A prominent and consistent indicator of climate change is the retreat of mountain glaciers, a worldwide phenomenon. Impacts on ice are also clear around the poles. The Arctic ice cap is shrinking, whilst in Antarctica, massive calving of the Larsen Ice Shelf combined with rapid rise in local temperatures around the Antarctic peninsula has led scientists to predict its complete disappearance within decades. Another widely observed impact is the ‘bleaching’ of coral reefs caused at least in part by rising sea-surface temperatures.

1. Solar radiation passes through the clear atmosphere. 2. Most radiation is absorbed by the Earth's surface and warms it. 3. Some solar radiation is reflected by the Earth and the atmosphere. 4. Infrared radiation is emitted from the Earth's surface. 5. Some of the infrared radiation is absorbed and re-emitted by the greenhouse gases.

“Climate change is happening. Over the 20th century, the global average temperature has risen by about 0.6 °C, and the mean temperature in Europe has increased by more than 0.9 °C. Globally, the 10 warmest years on record all occurred after 1991.” - European Commission strategy “Winning the Battle against Global Change”



Alpine Glacier: comparison of present to 1900: Pasterze Glacier in Kärtnen, Austria

Circa 1900 Present

Photo Source: Munich Society for Environmental Research

Temperature changes around the world in the last quarter of the 20th century

Temperature rise is due to Human activities

Source: Intergovernmental Panel on Climate Change, Third Assessment, Climate Change 2001: Synthesis Report



Viewfromtheotherside While answer of the absolute majority of scientists to the question “ Is there a Climate Change?” would be yes, this does not mean that 100 % of the scientists now support climate change as an absolute fact. There are alternative explanations 1. The sun may have warmed over the last 25 years and caused most if not all the warming

as discussed 2. Fossil fuel combustion releases heat directly to the atmosphere and will cause a warming

over the continents. 3. Urban heat islands are substantial (several degrees Celsius in many cases and larger than

the predicted anthropogenic greenhouse gases warming). Placing thermometers near cities and downwind of cities may lead to a warming that is falsely attributed to greenhouse gases.

4. Other explanations for the recent warming include increased intensity of El Niño, increase in aerosols in the atmosphere and reduction in atmospheric ozone.

The fact is that projecting climate change is a complex exercise. Although the basic mechanisms of climate change are straightforward, the final consequences for temperature and specific impacts can be extremely hard to quantify. The role of the oceans, which store vast amounts of heat and move it around in ocean currents, is complex. This introduces some deep uncertainties into efforts to quantify climate change. Greenhouse gases will in aggregate warm the surface, but by how much and how fast only becomes clearer as the warming signal emerges more and more clearly from amidst all the other influences. Even then, it is very hard to disentangle the effect of the oceans’ thermal inertia from the actual ‘climate sensitivity’ — slow warming may be a sign either of low atmospheric sensitivity, or it may show that decades more unavoidable climate change remains pent up in the slowly warming oceans. The chaotic nature of weather itself (as opposed to the ‘climate envelope’) makes regional climate changes and extreme events even harder to predict, and scientists are only slowly moving towards greater confidence about such effects. The understanding of climatic system is evolving, but the fundamentals are clear and supported by a long list of other accumulating impacts.ProbableimpactandimplicationsThere are clear trends in terms of warming, glacier retreat, sea-level rise, the migration and loss of species and ecosystems. There are various other predicted impacts of climate change; the list of these impacts could grow only longer as our understanding of multi-layered effects of climate change grows. Rising sea levels along with probable changes in storm patterns could have huge consequences for hundreds of millions of people living in coastal cities; delta regions such as the Nile Delta, lower Bangladesh, and parts of Florida, may be almost impossible to protect.



If sea level rises by 1 meter, the Maldives will disappear entirely, and in Grenada, up to 60 per cent of the beaches would disappear in some areas following a 50-centimetre level rise. Extreme weather events potentially have the greatest impacts on humans, but since they occur infrequently, trends are hard to prove. Warming increases evaporation and precipitation, and both aggregate rainfall and occurrences of ‘heavy precipitation events’ in northern mid-latitudes the principal cause of flooding, which have increased in recent decades. In tropical regions, the potential for more intense hurricanes and typhoons increases in a warmer world, but the data are sufficiently sparse and complex that the defining a trend remains in dispute. It may always be questionable to attribute any one particular weather event to climate change, because all weather events have multiple causes. But science is increasingly able to estimate ‘how much have past emissions increased the risk of such events?’ – and the chances, at least of extremes such as these, are rising. Following graph shows a dramatic rise in number of extreme weather events globally, partly driven by regional climatic factors (E. g. changes in precipitation and flooding). Source: Intergovernmental Panel on Climate Change, Third Assessment, Climate Change 2001: Synthesis Report Some of the very likely changes predicted (with more than 90% confidence) are Higher maximum temperatures, with more hot days and heat waves over nearly all land

areas. This would increase heat-related deaths, as well as heat-related stresses on crops. Higher minimum temperatures, fewer cold days, frost days and cold waves over nearly

all land areas. More intense precipitation events, resulting in increased floods, landslide, avalanche, and

mudslide damage, with increased soil erosion and increased flood run-off.

“It is not just island people who are at risk from climate change: 60% of humanity live in coastal areas and therefore share vulnerability to climate change and sea level rise. Low lying coastal areas in all countries are threatened, including agriculturally productive river deltas world wide.”



In densely populated areas such as the Indian subcontinent, it could create problems such as Rising seas and storms inundating the Ganges delta region; a more variable monsoon

undermining the agricultural foundations that feed a quarter of a billion people; and changing patterns of river flow as climate change impacts the Himalayan glaciers that feed the rivers, with corresponding international tensions across already volatile borders.

ActnowToolateortoosoon?The climate system is marked by the inertia involved. Atmospheric greenhouse gas concentrations will not stabilise until global greenhouse gas emissions are reduced to a small fraction of today’s levels, which is not expected by 2100. Even if the CO2 concentration stabilizes, global temperatures will continue to rise for decades as the oceans slowly adjust to the higher heat input. Sea levels will rise due to both thermal expansion and ice melt – effects which will accumulate over hundreds to thousands of years respectively.

CO2 Concentration, Temperature and sea level continue to stabilize over a long period

Source: Intergovernmental Panel on Climate Change, Third Assessment, Climate Change 2001: Synthesis Report

There are uncertainties about complex interacting systems such as North Atlantic Ocean circulation, monsoon in South Asia subcontinent, rainforest and permafrost. Their dynamics, stability and their limits are not well understood. Predicting specific changes to such complex systems is filled with uncertainty. By the time the limits are understood — they may already be crossed, possibly with dramatic consequences. The time to act on this issue is now, preparing in every possible way for adapting to climate change which is already pent up and unavoidable.



References The Climate Change Challenge: Scientific evidence and implications. Carbon Trust. IPCC, Third Assessment, Climate Change 2001: Synthesis Report UNFCCC (2005) climate change, small island developing States



EcoLogic Consultancy is a start-up consulting firm in the field of Environment Management. It provides services in wide spectrum of environmental field to help our clients to identify the opportunities, harness the potential, and solve their environmental challenges.

For further details and discussion, you can reach us at

[email protected] / [email protected]

020-400 96 279 / +91-90287 88430

www.ecologicconsultancy.in

cc impact implication_informative

Documents

global warming

current global climate

projecting climate change

climate changeencompasses

earths greenhouse blanket

earthsgreenhouse gases

gases act

recent warming