Global climate change
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The document discusses climate change and its causes. It defines climate change as a significant change in the average weather over a long period of time, typically 30 years. It notes that key factors that can change the climate include changes in greenhouse gases, volcanic eruptions, and human activities like releasing greenhouse gases. The document summarizes evidence that global temperatures have risen about 0.6°C since 1900, glaciers have retreated, sea levels have risen, and greenhouse gas levels are higher than in the last several million years. It discusses potential effects of climate change like sea level rise and changes to ecosystems.
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Global climate change
- 1. Climate Change: Fitting the pieces together Presented by: David Whiting
- 2. What is Climate Change? Climate is the average weather at a given point and time of year, over a long period (typically 30 years). We expect the weather to change a lot from day to day, but we expect the climate to remain relatively constant. If the climate doesn’t remain constant, we call it climate change. The key question is what is a significant change – and this depends upon the underlying level of climate variability Crucial to understand difference between climate change and climate variability…
- 3. Changes in: Sun’s output Earth’s orbit Drifting continents Volcanic eruptions Greenhouse gases What Changes Climate?
- 4. “Greenhouse effect”Increasing greenhouse gases trap more heat
- 5. Greenhouse gases Nitrous oxide Water Carbon dioxide Methane Sulfur hexafluoride
- 6. Global Climate Change • Identifiable change in the climate of Earth as a whole that lasts for an extended period of time (decades or longer) – When due to natural processes, it is usually referred to as global climate variability – Usually refers to changes forced by human activities that change the atmosphere
- 7. What causes EarthWhat causes Earth ’s’s climate to change?climate to change? Changes in the atmosphereChanges in the atmosphere Natural processesNatural processes VolcanoesVolcanoes Tectonic plate movementTectonic plate movement Changes in the sunChanges in the sun Human activities – any activity that releasesHuman activities – any activity that releases “greenhouse gases” into the atmosphere“greenhouse gases” into the atmosphere
- 10. Research • Almost 1000 studies dealing with different aspects of climate change have been conducted and published • So… how do we make sense of all this?
- 12. Global mean temperatures are rising faster with time 100 0.074±0.018 50 0.128±0.026 Warmest 12 years: 1998,2005,2003,2002,2004,2006, 2001,1997,1995,1999,1990,2000 Period Rate Years °/decade
- 13. Global surface temperature 1855-2010 How is this curve calculated?
- 14. CET Warming in Central England relativeto1772-1900 TemperaturerisedegC Hadley Centre
- 15. Other evidence of Climate Change • Glacier retreat 1875 2004
- 16. Glaciers and frozen ground are receding Area of seasonally frozen ground in NH has decreased by 7% from 1901 to 2002 Increased Glacier retreat since the early 1990s
- 17. Snow cover and Arctic sea ice are decreasing Spring snow cover shows 5% stepwise drop during 1980s Arctic sea ice area decreased by 2.7% per decade (Summer: -7.4%/decade)
- 18. Other evidence of Climate Change • Ocean heat content has increased • Temperatures in the Atlantic:
- 19. Sea-level from satellites: 4 cm rise in last 10 years
- 20. Some aspects of climate have not been observed to change: • Tornadoes • Dust-storms • Hail • Lightning • Antarctic sea ice Direct Observations of Recent Climate Change
- 21. 21
- 22. Summary (Observations) Global surface temperatures have risen by about 0.6°C since 1900 It is likely that this warming is larger than for any century since 200AD, and that the 1990s were the warmest decade in the last millennium. The warming differs in different parts of the world, but over the last 25 years, almost everywhere has warmed, and very few places have cooled. Other changes have occurred, e.g.: Sea level has risen by about 20 cm, Ocean heat content has increased, Almost all mountain glaciers have retreated Coincident with this global warming, levels of CO2 (and other ‘greenhouse’ gases) have dramatically increased, to levels higher than those experienced for maybe millions of years. Next: are temperatures and atmospheric composition linked?
- 24. How do we know?
- 25. Sea-level rise projections : a few inches to a few feet •2 ft: U.S. would lose 10,000 square miles •3 ft: Would inundate Miami •Affects erosion, loss of wetlands, freshwater supplies •Half of the world’s population lives along coasts •Big question: Ice sheets
- 27. How sure are scientists? What don’t we know? • Is there some critical piece of the about climate process we don’t understand? • How and when will our fossil fuel use change? • Will future , yet-to-be-discovered technologies mitigate the problem? • How will changing economics, global population, and political processes affect our ability to tackle the problem?
- 28. Produce more fuel-efficient vehicles Reduce vehicle use Improve energy-efficiency in buildings Develop carbon capture and storage processes Triple nuclear power Increase solar power Decrease deforestation/plant forests Improve soil carbon management strategies
- 29. Individual actions Use mass transit, bike, walk, roller skate Tune up your furnace Unplug appliances or plug into a power strip and switch it off Buy water-saving appliances and toilets; installing low-flow shower heads. Caulk, weatherstrip, insulate, and replace old windows Buy products with a U.S. EPA Energy Star label
- 30. Sea-level from satellites: 4 cm rise in last 10 years
- 31. Some aspects of climate have not been observed to change: • Tornadoes • Dust-storms • Hail • Lightning • Antarctic sea ice Direct Observations of Recent Climate Change
- 32. 32
- 33. The global climate change debate IPCC Main findings on climate change It’s already happening It’s going to continue happening The rate of change is alarming Extreme weather more frequently IPCC Fourth Assessment Report, 2007
- 34. Origin and effects of global warming use of fossil fuels (oil, coal, gas) rising concentrations of greenhouse gas rising temperatures (global warming) changes in local weather extremes changes in local average climate
- 35. Disaster trends Changing disaster patterns: geo- physical hydro- meteorological epidemics, insect infestations 100 200 300 0 400 ‘90 Source: CRED ‘91 ‘92 ‘93 ‘94 ‘95 ‘96 ‘97 ‘98 ‘99 ‘00 ‘01 ‘02 ‘03 ‘04 ‘05 ‘06 Numberofdisasters weather related disasters doubled over the past 2 decades increase small- and medium-scale disasters more uncertainties
- 36. Sea level rise - sea level rise will bring large coastal areas at risk - salt water intrusion threatens water supply and food security - impacts already being felt particularly during storm surge
- 37. Melting ice reduction in water supplies glacial lake outburst floods Qori Kalis Glacier, Quelccaya Ice Cap, Peru 1978 2002
- 38. Health and climate change - shift of diseases to new areas - increase of water borne diseases after floods - increase of diseases due to higher temperatures, humidity or drought
- 39. Summary (Observations) • Global surface temperatures have risen by about 0.6°C since 1900 • It is likely that this warming is larger than for any century since 200AD, and that the 1990s were the warmest decade in the last millennium. • The warming differs in different parts of the world, but over the last 25 years, almost everywhere has warmed, and very few places have cooled. • Other changes have occurred, e.g.: – Sea level has risen by about 20 cm, – Ocean heat content has increased, – Almost all mountain glaciers have retreated • Coincident with this global warming, levels of CO2 (and other ‘greenhouse’ gases) have dramatically increased, to levels higher than those experienced for maybe millions of years. • Next: are temperatures and atmospheric composition linked?
Editor's Notes
- The topic of climate change is like a puzzle with many different pieces—oceans, the atmosphere, ecosystems, polar ice, natural and human influences. Scientists have been working on this puzzle for more than a century, and while there are still gaps in our knowledge, most experts feel we have the puzzle is complete enough to show that human activities are having an adverse effect on our planet. This talks looks at many of those puzzle pieces, the evidence behind them, and the conclusions we can draw from them.
- Scientists have a good understanding of what has changed earth’s climate in the past: Incoming solar radiation is the main climate driver. Its energy output increased about 0.1% from 1750 to 1950, increasing temperatures by 0.2°F (0.1°C) in the first part of the 20th century. But since 1979, when we began taking measurements from space, the data show no long-term change in total solar energy, even though Earth has been warming. Repetitive cycles in Earth’s orbit that occur over tens of thousands of years can influence the angle and timing of sunlight. In the distant past, drifting continents make a big difference in climate over millions of years by changing ice caps at the poles and by altering ocean currents, which transport heat and cold throughout the ocean depths. Huge volcanic eruptions can cool Earth by injecting ash and tiny particles into the stratosphere. Changes in the concentration of greenhouse gases, which occur both naturally and as a result of human activities, also influence Earth’s climate.
- [Image 1] Earth’s surface absorbs heat from the sun and then re-radiates it back into the atmosphere and to space. [click, Image 2] Much of this heat is absorbed by greenhouse gases, which then send the heat back to the surface, to other greenhouse gas molecules, or out to space. Though only 1% of atmospheric gases are greenhouse gases, they are extremely powerful heat trappers. By burning fossil fuels faster and faster, humans are effectively piling on more blankets, heating the planet so much and so quickly that it’s hard for Mother Nature and human societies to adapt.
- What are greenhouse gases? Any gases that cause the “greenhouse effect!” WATER VAPOUR METHANE CARBONE DIOXIDE NITROUS OXIDE While there are many substances that act as greenhouse gases, two of the most important are water and carbon dioxide, or CO2.
- 89% of current changes in ecosystems are consistent with changes expected due to global climate change Greenhouse gases as discussed levels in atmosphere have increased greatly due to human activities since 1750 and now far exceed previous levels / Carbon dioxide has increased by approximately 80% since 1970 Warming and sea level rise will continue and will probably occur more quickly than what we’ve already seen Even if greenhouse gases are stabilized, this will probably continue to occur for centuries Some effects may be permanent Effects on Ecosystems Coral systems cannot handle higher temperatures well Wildfires will increase Up to 30% of species will be at increased risk for extinction due to the rapid changes in their ecosystems
- Increased warmth has also affected living things. For example, the Japanese keep very detailed records on the blossoming of their Tokyo cherry trees, so they know they are blooming 5 days earlier on average than they were 50 years ago. Also mosquitoes, birds, and insects are moving north in the Northern Hemisphere.
- Scientists learn about the past climate conditions from such things as tree ring analysis, fossil evidence, and analysis of patterns and chemical composition in coral skeletons and ice cores.
- The oceans will continue their rise in the coming century. The IPCC’s best estimates range from a few inches to a few feet by 2100. If the rise is 2 feet, the US could lose 10,000 square miles, If they rise three, they will inundate Miami and most of coastal Florida. Sea-level rise also increases coastal erosion and the loss of coastal wetlands, and saltwater spoils freshwater drinking supplies. Coastal populations become even more vulnerable to storm surge and flooding. Considering that half of the world’s population lives near coasts, sea-level rise is a serious concern. The big unknown in all this is how much the planet’s ice sheets will melt.
- [Image 1] A warming planet means continuing changes in its ecosystems. As the oceans absorb more carbon dioxide, the chemistry of the ocean changes, putting many sea creatures at risk. The IPCC projects that by 2100 the pH of the ocean will drop to its lowest point in at least 20 million years. [click, Image 2] As temperatures get milder, mosquitoes, ticks, rodents, and other disease carriers will expand their range, particularly in developing countries. Here in the U.S., dengue hemorrhagic fever, a tropical, mosquito-borne disease, hit for the first time in modern times in 2005 in the Lower Rio Grande Valley. [click, Image 3] Warmer temperatures will also mean less snow overall at certain latitudes because more will fall as rain, and the snow that does fall will melt faster. This affects people living in areas that depend on snow-fed reservoirs for water. [click, Image 4] The IPCC projects increases of 5-20% in crop yields in the first decades of this century. but the crops will be more prone to failure if climate variability increases and precipitation becomes less dependable. And ironically, with higher temperatures comes an increased potential for killing freezes. This is because plants start growing earlier, making them more vulnerable to sudden spring-time cold spells.
- Nothing in science is 100% certain There are no laboratory experiments that can tell us what the future will be—the planet IS the test tube [click to reveal bullets] What don’t we know? Is there some climate process we don’t know about? So far, research over the years has strengthened the conclusion that humans are adversely influencing climate, but scientific knowledge is still evolving We don’t know how things might change in the future, such as Will alternative energy sources become widely available? How soon? Will some yet-to-be-discovered technology be able to clean CO2 out of the air? How will changing economics, global population, and political processes affect our ability to tackle the problem?
- Here are examples of 8 technologies that could save 8 billion tons, or 8 wedges, of carbon. Some of these we could do right away, while others are based on technologies still being studied, such as capturing and storing carbon. [Details on strategies: Efficient vehicles: Double car fuel efficiency in 2055 from 30 miles per gallon (mpg) to 60 mpg Reduced vehicle use: Halve the miles traveled by the world’s cars in 2055 Efficient buildings: Cut emissions by 25% in all buildings CCS electricity: Capture and store carbon from 800 large coal power plants or 1600 large natural gas power plants Triple the world’s current nuclear capacity Solar electricity: Increase solar capacity 700 times Forest storage: Halve global deforestation and double forest planting in 50 years Soil storage: Apply carbon management strategies to all of the world’s farm fields] This list represents only some of the possible strategies, but choosing strategies will not be easy. However, the longer we wait to reduce emissions, the higher the target will need to be, and the more adaptation will be necessary. In 2004, when the wedges concept was first introduced, the target was only 7 billion tons.
- As you can see, there are many ways society can approach the struggle to reduce carbon emissions, but there is no single solution. Many of the strategies mentioned are the realm of governments. And the ever-growing world population means that we’ll have to work that much harder to reduce global emissions. But on an individual level, there are many things you can do to make a difference. [click to reveal examples] Lots of other ideas are available on the Internet.
- The Intergovernmental Panel on Climate Change (IPCC) is a UN agency consisting of more than 2000 climate scientist from all over the world that review all scientific data on climate change. The RCCC closely looks at the publication of the IPCC reports to be well informed of the current international scientific consensus on climate change. The latest report was launched in 2007 and this report was an eye-opener to the larger public. Its statements were clear and alarming: climate change is now unequivocal, it is bound to continue at an alarming rate unless substantial measures are taken to reduce greenhouse gas emissions and it already is and will continue to bring the world more extreme weather events.
- Anthropogenic/ human induced global warming results in changes to local average climate systems and in local weather conditions. In the second part of this presentation we will further look at these local changes. We will demonstrate this with graphs that show changes in temperature.
- An increase in the number of weather related natural disasters According to the IFRC World Disasters Report 2006 the last ten years saw an increase of reported natural disasters. Until 1997 this number was around 200 per year. Since that year the average number went to more than 300 a year, reaching almost 400 per year in 2006?. This increase is due to the rising number of weather related disasters, such as floods and storms. The increase is particularly in small- and medium-scale disasters, sometimes referred to as ‘forgotten disasters’. Occurrence of geophysical disasters (such as earthquakes, volcano eruptions and tsunamis) have remained more or less the same.
- Increases in the number of high sea level events are being recorded. SEA LEVEL RISE CAUSES STRESS FOR PEOPLE LIVING IN COASTAL AREAS ALL AROUND THE WORLD and is exacerbated by phenomenon such as storm surges and king tides. FURTHERMORE IT´S A THREAT TO WATER RESOURCES BECAUSE OF THE SALINATION OF GROUND WATER AFTER INUNDATIONS. IT OBVIOUSLY HAS CONSEQUENCES FOR FOOD SECURITY AS WELL BECAUSE INUNDATIONS LEAD TO DESTRUCTION OF LAND AND FOOD SUPPLIES. This could force people to seek living space elsewhere. The impacts of sea level rise can be exacerbated by environmental degradation such as sand mining and dense coastal living. NOTE: sea level rise is predicted to be 80cm if you include ice dynamics as published by science in 2008!!!! IPCC recognizes that ice dynamics are not included in their predictions; Ice dynamics is a complex phenomenon of the growing and melt off variability of ice sheets (statement doesn’t make sense), including the possible break offs of ice sheets.
- Cities such as Peru are completely dependent on water supplies offered by glaciers. A constant melt during the dry season is of utmost importance to continue water supply. Glaciers are then usually ‘recharged’ with more snowfall during the wet season. If the rate of melting is greater than the rate of replenishment, the glaciers will eventually disappear, having long term implications for water security. Glacial melt can also cause a build of water in lakes, sometimes causing ‘glacial lake outburst’ floods in places such as Nepal.
- CLIMATE CHANGE WILL LEAD TO A SHIFT OF VECTOR BORNE (or insect carried) DISEASES such as MALARIA, DENGUE, WEST NILE VIRUS, LEISHMANIASIS ( IS A PARASITE – CAUSES WOUNDS/ INFECTIONS AND MISFORMING OF HEAD AND LIMBS, FEVER, CUF LYME SCHISTOSOMIASIS (EGGS: INFECTIOUS DESEASE – STOMACH AND INTESTINES INFLICTION, LEADING TO FEVER, ILLNES, CUF ETC.) MOSQUITOS CARRYING THESE VIRUSES SHIFT TO NEW TERRITORIES AND SURVIVE IN MORE PLACES WHERE THEY NEVER OCCURRED BEFORE BECAUSE OF THE LARGER AREAS WITH HIGHER TEMPERATURES. IPCC also describes an increase of diseases due to higher temperatures, humidity or drought: diarrheal disease, cholera, meningitis, skin disease, food poisoning
- Scientists are still working on the puzzle. The IPCC’s 5th Assessment Report is planned for 2013-2014. Climate models are being improved, more data is being collected. However, the puzzle is already complete enough to know we need to take action.