PERUBAHAN IKLIM : PENGERTIAN, PARAMETER & SKENARIO -MA-

MKP. PENGELOLAAN LINGKUNGAN TERKAIT PERUBAHAN IKLIM

MINGGU KE 2

KEY CONCEPTS: PERUBAHAN IKLIM

1. PENGERTIAN 2. PARAMETER 3. SKENARIO PERUBAHAN IKLIM

Kasus: – Indonesia, medio Oct 2008. Catatan BKG suhu udara siang hari

mencapai 38C di Surabaya, demikian pula di kota-kota di Jawa seperti Jakarta, Bandung, Semarang dll.

Apakah kasus diatas merupakan perubahan iklim?

PENGERTIAN PERUBAHAN IKLIM – PERUBAHAN UNSUR-UNSUR IKLIM DALAM WAKTU JANGKA PANJANG (50-100

TAHUN) YANG DIPENGARUHI OLEH KEGIATAN MANUSIA YANG MENGHASILKAN GAS RUMAH KACA (Murdiyarso, 2003) GAS RUMAH KACA CO2, NO, O3, Metan dan CFC.

– Climate change Climate change refers to a change in the state of the climate that can be identified (e.g., by using statistical tests) by changes in the mean and/or the variability of its properties, and that persists for an extended period, typically decades or longer. Climate change may be due to natural internal processes or external forcings such as modulations of the solar cycles, volcanic eruptions and persistent anthropogenic changes in the composition of the atmosphere or in land use (IPCC, AR5, 2013).

– a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods (UNFCCC)

PARAMETER – PERUBAHAN IKLIM DICIRIKN OLEH BERUBAHNYA NILAI RATA-

RATA ATAU MEDIAN DAN KERAGAMAN DARI UNSUR IKLIM :– SUHU LAND AIR SURFACE, SEA – MENCAIRNYA ES DI KUTUB – CURAH HUJAN– SEA LEVEL RISE

SUHU – Amatan data suhu

dalam periode waktu yang panjang kecenderungan naik/fluktuasinya semakin sering membesar

– The atmospheric concentrations of carbon dioxide, methane,and nitrous oxide have increased to levels unprecedented in at least the last 800,000 years. Carbon dioxide concentrations have increased by 40% since pre-industrial times, primarily from fossil fuel emissions and secondarily from net land use change emissions.

Total radiative forcing is positive and has led to uptake ofenergy by the climate system

Energy in Climate System Ocean warming dominates the increase in energy stored in the climate system, accounting for more than 90% of the energy accumulated between 1971 and 2010 (high confidence).

The largest contribution to total radiative forcing is caused by the increase in the atmospheric concentration of CO2 since 1750

Human influence on the climate system is clear

CLIMATE PROJECTION SCENARIOS

The Emissions Scenarios of the Special Report on Emissions Scenarios (SRES)*

– A1. The A1 storyline and scenario family describes a future world of very rapid economic growth, global population that peaks in mid-century and declines thereafter, and the rapid introduction of new and more efficient technologies. Major underlying themes are convergence among regions, capacity building and increased cultural and social interactions, with a substantial reduction in regional differences in per capita income. The three A1 groups are distinguished by their technological emphasis: – fossil intensive (A1FI), – non-fossil energy sources (A1T), – or a balance across all sources (A1B) *IPCC AR 4, 2007

... SRES:– A2. a very heterogeneous world. The underlying theme is self-reliance and

preservation of local identities, continuously increasing population. Economic development is primarily regionally oriented and per capita economic growth and technological change more fragmented and slower than other storylines.

– B1. convergent world with the same global population, that peaks in mid-century and declines thereafter, with rapid change in economic structures toward a service and information economy, with reductions in material intensity and the introduction of clean and resource-efficient technologies. The emphasis is on global solutions to economic, social and environmental sustainability, but without additional climate initiatives.

– B2. a world in which the emphasis is on local solutions to economic, social and environmental sustainability, continuously increasing global population, at a rate lower than A2, intermediate levels of economic development. oriented towards environmental protection and social equity, it focuses on local and regional levels.

The four SRES scenario families of the Fourth Assessment Report vs. projected global average surface warming until 2100

AR4(Summary; PDF) More economic focus More environmental focus

Globalisation(homogeneous world)

A1rapid economic growth(groups: A1T; A1B; A1Fl)

1.4 - 6.4 °C

B1global environmental

sustainability 1.1 - 2.9 °C

Regionalisation(heterogeneous world)

A2regionally oriented

economic development2.0 - 5.4 °C

B2local environmental

sustainability1.4 - 3.8 °C

Asumsi2 dalam SRES– Perubahan orientasi pembangunan dari yang hanya

mementingkan pembangunan ekonomi ke arah yang juga memperhatikan lingkungan

– Perubahan kerjasama antar negara dari yang lebih independen ke arah yang lebih saling tergantung sama lainnya.

– Hasil kajian ilmiah yerkini menyatakan bahwa kenikan suhu global melebihi 2oC pada tahun 2050 akan menimbulkan masalah perubahan iklim yang semakin sulit dikendalikan, oleh karena itu IPCC menyusun skenario emisi yang disbut dengan RCP (Representative Concentration Pathways) dimana skenario disusun berdasarkan target konsentrasi GRK yang ingin dicapai.

SKENARIO PROYEKSI PERUBAHAN IKLIM RCP IPCC AR5 2013

– Representative Concentration Pathways (RCPs) Scenarios that include time series of emissions and concentrations of the full suite of greenhouse gases and aerosols and chemically active gases, as well as land use/land cover (Moss et al., 2008). The word representative signifies that each RCP provides only one of many possible scenarios that would lead to the specific radiative forcing characteristics. The term pathway emphasizes that not only the long-term concentration levels are of interest, but also the trajectory taken over time to reach that outcome. (Moss et al., 2010).

Radiative Forcing (RF)–  the difference of insolation (sunlight) absorbed by the

Earth and energy radiated back to space. Typically, radiative forcing is quantified at the tropopause in units of watts per square meter of the Earth's surface. A positive forcing (more incoming energy) warms the system, while negative forcing (more outgoing energy) cools it. Causes of radiative forcing include changes in insolation and the concentrations of radiatively active gases, commonly known as greenhouse gases and aerosols.

Shindell, Drew (2013). "Radiative Forcing in the AR5" (PDF). Retrieved August 2015.

RCP Scenarios• Radiative forcing peaks at approx 3 W/m2 and

decline before 2100RCP 2.6 • Stabilization pathways in which radiative forcing is

stabilized at approx. 4.5 W/m2 after 2100RCP 4.5• Stabilization pathways in which radiative forcing

is stabilized at approx. 6.0 W/m2 after 2100RCP 6.0• Bussines as usual scenario Which have radiative

forcing grater than 8.5 W/m2RCP 8.5

RCPs

Each RCP provides spatially resolved data sets of land use change and sector-based emissions of air pollutants, and it specifies annual greenhouse gas concentrations and anthropogenic emissions up to 2100. RCPs are based on a combination of integrated assessment models, simple climate models, atmospheric chemistry and global carbon cycle models.

SRES VS RCP

From Rogelj et.al. 2012

PROYEKSI SUHU DG RCPs

Limiting climate change will require substantial and sustained reduction of greenhouse gas emission.

Standar emisi untuk 2oC 790 Jt t CEmisi CO2 s/d 2013 -535 Jt t C

Emisi yang tersisa 255 jt t C

Emisi CO2 di 2013 9,9 juta t C 25 tahun?

IMPLIKASI THD ICE EXTENT

IMPLIKASI THD SEA LEVEL RISE

RCP 8.5 on precipitation

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